[ETA] You don't need to ask for permission to use the stamp in your journal/shoutboard etc, go right ahead, that's what it's there for ^^

Art Theft
It's not cute
It's not flattering
It's not acceptable

Admitting that 'it's bound to happen' is as good as giving art thiefs free reign to do as they like. We shouldn't HAVE to slap huge, ugly watermarks over our work. But we do.

I've had art thiefs claim before that they did it because they love my work.
If you love something so much then show the artist some respect, don't steal from them, you're only hurting them and everyone else that enjoys their work.

Even if a piece of art is posted online it is still protected by copyright law, posting something online does NOT make it yours to do as you want with (general 'you' here). But then I guess I'm preaching to the choir aren't I?