I've had scammers on CL demand "ransom" or else they would use my phone number and E-mail address as a forged origin point for their spam. Doesn't bug me -- last time I tried listing something on CL, I used a prepaid phone and a temporary E-mail address. When someone tried to extort me, I replied back, encouraging them to go right ahead, and questioned their mental capacity in a very blunt fashion. Since I was done with CL completely, I then deleted the E-mail address, locked (too many PIN and PUK guesses cause the card fry itself) and destroyed the SIM card, and when I passed by a nearby store, donated the phone to a military charity.