Browsing mods yesterday... viewed a Demo link and BAM! Ripped style... this will never end and best not to think about it unless your developing a solution... good attempt Xphusion w/ the watermarks but when they find one of your clients site not using the watermarked images as they have the paid version... it's thiers then. Also what about all the new downloader add-ons for firefox and IE etc??
You can just about DL entire forums these days and piece them together which is sad, thank goodness not everyone is code savvy eh?
Like I said, don't let it stress you UNTIL you NEED to address the issue in regards to yourself. I do take the time to report suspected pirated themes to their owners though.... that is less than a minute process and I consider it respectful to say the least.
S-MAN
Edit: I still LOVE that sig Shelley C