hmmmm...I had this argument with someone at some point. we can to the conclusion most designers don't like their hard work stolen from them...and If it has to go the it shall go at a price, yet most artist and some multimedia designer (them in particular) don't really mind and take their product being take as good thing, because that means someone out there like their work and is using it in some way or another. and in that sense it keep the people coming back to see more of your work...
...personally I love putting my tag on my work depending on my liking of it...if I like it, its will have the 1ove...M on it, then again thats not quite a watermark is it!