Is this stealing?

[encoder]

Just like everyone else said, it is not stealing but it will not degrade you if you ask them about it. Libraries are for public use and when they have a wifi service then it is also for the use of the patrons of that library. If they don't want others to use their connection, then it should have a password before you can use it.

[alexis]

I think if the setup is secure, and you are actually "breaking in" then yes, but what happens when its not secure and the person owning it still says "Well, you should not be on there"?

[Satmancrothers]

I wouldn't worry about it at all. In fact you're helping to pay for it. They have IT people, IT people are hawkish about security, which means you wouldn't have access if they didn't want you too unless you're cracking encryption.