I fly out of FAT and end up on the MQ code share to LAX a lot. The only time MQ has waived the baggage fee was for intl flights. The other times I have paid the $25 and then used the on-line customer service contact form to complain and have received $25 voucher.

The thing I found interesting is that many times DL is paying MQ all of $10 for the flight. I'm sure MQ enjoys tacking on the $25 baggage fee.

MO