(U.S.) Is it illegal to post Occupy flyers on bank buildings/property?

It is vandalizing private property. You probably won’t go to jail, but the bank can sue you to replace any damaged equipment or to pay for any cleaning they have to do as a result of putting up the signs.

If the judge is in a really bad mood, you could be responsible for lost income too.

They have cameras on cash machines so they can get pictures of people who put stickers on the machines.

“It is not what a lawyer tells me I may do; but what humanity, reason, and justice tell me I ought to do.” – Edmund Burke, 1775

Also, ATM machines have security cameras. Not a wise plan.

Do what you think is right.
The rebellion of the founders against the British Empire was High Treason and thus illegal. Did not stop them from doing it.
And remember that putting some stickers on a machine will not result in the deaths of countless proud British Patriots at the hands of colonial traitors.

Occupy is a protest against a set of things that are legal despite the fact that they are clearly unethical. We should not be stopped from doing what is ethical, then, just because it is illegal. Indeed, civil disobedience is defined in terms of a refusal to obey certain laws. Let this be one of them.

It depends. Local regulations vary, but where I live, it is illegal to post any sticker or notice anywhere without proper permits.

It is illegal is post any flyers on any building without the permission of the business housed there. And, where I am, it is illegal to post flyers on phone poles or any other street signs.

@SmashTheState

Damn, son! You sure do come out with some good stuff! : ))