As a TA, I wouldn't even consider trying to 'swipe' someone's miles. But that's just me and I can guess there are a few less reputable types in this industry. Why risk the airline's rather if discovered as well?
It's also been my experience that depending what booking vehicle the agent is using, it does kick back mismatched names and FF numbers.
While we're on the subject, I have taken advantage of legitimate offers like NW 'refer a friend' who didn't have a FF account, so I signed up clients and scored the referral bonus. That's not unethical, to me.
[This message has been edited by tcook052 (edited 05-24-2003).]