FRAUD ALERT. Let me give you a warning.

I wouldn't post any personal information for the world to see. (that's why we have PM's) Scammers and spammers would love it if you would.
Exactly.

But a watermark would work. I've run into this in the past when I've sold-off some rather expensive audio gear, and I've learned that a watermark splashed across my picture(s) works wonders to allay Buyers fears against potential fraud.