Wirelessly posted (Mozilla/5.0 (iPhone; CPU iPhone OS 5_0_1 like Mac OS X) AppleWebKit/534.46 (KHTML, like Gecko) Version/5.1 Mobile/9A405 Safari/7534.48.3)
Happened to lucky before:
http://boardingarea.com/blogs/onemileatatime/2011/06/01/someone-decided-to-cancel-my-tickets-remember-to-protect-your-travel-plans/
So you do have to watch out who gets ahold if your PNR, unless you call and put a password on it. I believe all credits have to be used by the name of the person on the ticket so less danger from people ripping you off.