If you are ever a victim of someone stealing your photos (watermarks can be removed with photoshop programs), send them a "take down" letter before contacting them directly. Example http://www.ipwatchdog.com/2009/07/06/sample-dmca-take-down-letter/id=4501/
I have been victim a few times and usually play the nice guy and simply ask them to remove them; however, one caker has done it twice to me (and has used others' photos I recognized from CC).
Once the photo is gone, I've lost my proof. From now on, I will send the letter first.
If you ever get this excuse, "I have someone that tends to my website for me and they took some photos that had been sent requesting could we make something similar. I had them in a file called Client requests and he took the wrong photos," it's not the truth.
Lol...no that's the most used lie of all!