Eastbay1K: I think you're (as they say) "assuming facts not in evidence".

I don't know that UA "suffered a rash of fraud". That's an assumption on your part. Plus I don't know that UA would necessarily be the victim. If they take reasonable precautions, and there is a chargeback that is upheld by the card issuer, the bank might well be the victim. If the airline requires that the cardholder be one of the passengers travelling on the record (I don't know if they do, but they should), then IMHO there is little opportunity for fraud.

Besides, if it is true that 1P's and 1K's are exempt from the rule, is United's risk of fraud really significantly greater as to 2P's? I don't particularly think so.