Originally Posted by
geometry
actually, it was the airline check-in agent's suggestion... (a Star Alliance airline, not United) she weighed my friend / co-worker's bag which was a "little" overweight and suggested that it be checked as "my" bag... I figured that if she suggested it, then it must be okay? However, I just want to know if there are any rules against doing this. If there are, I'll just flatly refuse to do it next time.
It's your choice to check another travelers bag as your own and not a rule violation -- but at some non-US locations, you may be asked if you packed the bag.
If you were not traveling and someone used your card, that's a different issue and could become a problem if discovered.