I was asking if somebody generated a BTC address, checked the BTC network, saw it already had BTC in it, then took it, if that is illegal. I am pretty certain it isn't. If you say it is and a BTC developer heard you I'm sure he'd give you a great big slap.
First of all, what are you talking about here is not possible. You can't just generate an address that already has a Bitcoin in it, because you can't generate the same address twice.
Are you serious right now? Your knowledge of Bitcoin is obviously very small. It's is 100% possible two people can get generate the same address but it is really really REALLY unlikely. Please don't talk about things you know nothing about to begin with.
I could say that these kind of bugs of addresses is a very rare thing to happen because all new generated address are completely unique but we cant really avoid some flaws or circumstances. There are really people talk too much into things without any proper knowledge with it. In situation of OP its not considered as stealing for me.