If it's an open network it's to be expected. A "thanks for leaving your connection open for everyone to use" might be in order every now and then.

But if the reason it's open is because they don't know how to secure it, your helping them to figure that out might earn you the right to use it even after it's closed.

Something to keep in mind (if it's your network that's open) is that if someone uses your connection to commit a crime you can be held responsible even if it happens without your knowledge. That's also a good reason not to let someone who isn't paying for it to use it because there's no legal recourse by you if they don't have a signed agreement with the provider but you do.

But ethically, no, it's not okay to use someone else's stuff without their permission. Just like you wouldn't want people walking into your home just because you left the door open.

I have to agree with all of the points @silverhammer made.

I have to add that you do not know what the person who is hosting that network may be doing. In my college dorms, there were many Engineers. Some of them like to play pranks and others could be malicious with "unsecured" networks.

As pranks, someone can add scripts to a router that can redirect traffic or make things look weird. To be malicious, they can record everything you do. That includes transmission of non-encrypted data. That data would reveal what websites you visit, what data you look at, and possibly some passwords on ill-protected websites.

A man in FL was just arrested for it. There is a federal law against it, but it's aimed more at hackers. State laws are a little easier to prosecute under. It's definitely unauthorized use, no matter how you word it.

http://www.sptimes.com/2005/07/04/State/Wi_Fi_cloaks_a_new_br.shtml

Excellent Question! I have wondered about this before. After moving into an apartment and getting a laptop, I was thrilled to find that there was a connection. I used it for awhile before considering whether this was okay. I decided it was okay. If someone leaves there system open, I consider that permission to use the service. I have since gotten my own service and leave it open. Whether it is someone passing by or a neighbor that don't have service yet, I want to be of help. That's my decision.

I did a little research after seeing your question and came upon a great article that discusses this issue. It covers both the pro's and con's of the issue. You can read the article (here). It is titled '''The ethics of "stealing" a WiFi connection'''.

The article points out that in some places it is illegal to access "an unsecured, wide-open WiFi network without permission". It is not just in the UK either, Illinois and Michigan have outlawed the practice. In the article, Mr. Bangeman gives some good examples that set precedence for the use of these signals (TV and Radio). He also cautions people to not let leave their own connections open! Go figure.

Silverhammer's suggestion of offering to help them secure it in exchange for being allowed to use it is a great one! I do not have an open connection, but if I did, I would probably understand if someone was in a bind and needed to use it for a little while. That being said, I would not approve of them piggybacking off me long term. If you need to use it regularly, it's probably best to ask them first.

should not use it with out his permission

Is it ok to steal? Got your answer?

It’s done daily, but it isn’t ethical, and can be harmful. There is a simple rule: if you are receiving something that requires payment for free, you are stealing. There is no other way around it.

I personally don’t see the difference between “piggybacking” (see: stealing) someone’s Internet connection and slipping a pair of sunglasses in your pocket at the store. It’s theft.

Also, if you choose to download files or stream video, it is possible that you are slowing down the connection speed for the PAYING customer. Definitely uncool.

I know folks tell themselves all sorts of things (it’s called rationalizing) to make something like this right in their mind, but it isn’t. If you want free Internet, go to a WiFi supported coffee shop or café. Then it isn’t petty theft.

There are some places that consider it to be theft of communication that imposes fines, but overall it is legal unless defines in that state. Please be aware that if you do connect to their network you are succeptible to them possibly hacking into your computer where as they may be able to steal personal information.

Since the question posed was "is it ok" rather than "is it legal" I'll assume you're concerned about the ethics of the matter rather than possible legal repercussions. Further, you do not ask "is it a good idea" so I'll bypass the risks you incur by piggybacking on someone else's wifi connection.

Practically speaking, piggybacking like that is not identical to shoplifting or stealing a physical item. When you take a physical item without paying for it, that item is taken from its rightful owner, who would then either have to do without, or else buy a replacement. With something like access to broadband, where the bandwidth is almost never a limiting factor (i.e. the service is faster than what the paying customer uses most of the time) even the slow-down resulting from your piggybacking is negligible (unless you use it to download huge files or for heavy-duty interactive gaming).

The above is not to say, however, that it is ethically acceptable, or "ok." Consider what would happen if you were not the only one piggybacking on the open connection. At some point the paying customer would be impacted, which is unacceptable.

Another issue is that the service provider is basing its pricing on expected bandwidth use, and the cost of providing that service. If many people piggyback, the total usage of the service goes up, but the revenue does not. This results in increased costs to the provider, which will then pass along the increased costs to its paying customers. Claiming that your minimal use is not going to cause such a result does not wash. If piggybacking is "ok," you'd have to consider what the ultimate result would be of many people doing so.

Thus it is not "ok" to piggyback on an open wifi connection. Further, it would not be "ok" even if your neighbor agrees to it, since there is the additional stake-holder in this scenario - the service provider, who you are not asking for permission, and were you to ask, you would not expect a positive answer.

The one possible ethical exception (not necessarily making it legal or a smart idea) is if you are already a paying customer of the same broadband service, and are piggybacking to a minimal extent on someone else's connection in a way that does not affect their actual usage.