Unfortuneately there's nothing the airlines can do about it except not hire ANY military, which they really can't do. USERRA is very clear that employers have to let Guard/Reservists go if they are on military orders, and, if you remember, the country is at war.

They have to actually be on orders though...(the system is kind of complicated and not just any Guard or Reserve job qualifies).

I know guys who have abused the system (mostly at SWA) and it does leave a bad taste in everyone's mouth. But the last time I was at Balad in full kevlar hiding under a desk while the intercom blared "incoming...incoming", I really didn't feel like the airline guys who were with me were gaming the system.