error in your favor, what would you do?

[jb9]

So, just theoretically speaking here, if you had a weird disconnect/crash at poker site and received an e-mail stating that they had reviewed what happened and credited your account accordingly and you checked your account and realized they had made an error in your favor (let's say it's about $100), what is the proper course of action? Swift, proactive honesty? Let them figure it out themselves? Take the money and run?

Just wondering, in case, uh, this ever comes up...