One issue is airlines are still fighting the last battle. When I was a 727 FO making 60 bucks an hour, it was a huge financial incentive to go on orders or do a UTA/FTP as I made more in the military than I did the first couple years here.
These days, guys are making $125-$150 an hour year 2 as 757 or MD/777/Bus FOs. Any day off work is often a financial hit, not a perk.
I know there were guys who probably dropped a lot of trips in the past, but with the SO seat gone and a higher pay rate these days, I suspect it won't be as big a problem for FDX, SWA, and the rest of the companies as it was in the decade of chapter 7/13 airlines and concessionary contracts.
The few guys I know on mil leave are all F-22 guys, and they are all on leave because they are extremely capable guys that have been by-name requested for specific, high profile high demand taskings. I know one personally that was digging flying the MD around the globe, and only did this because his leadership begged him to come back and help.
There may be some bad apples out there. Most of the guys I know are warriors and patriots, just trying to keep 2 sets of bosses and a momma happy. As a guy who did it six years, I can say without reservation it can be a very difficult mix. Generally you end up feeling like your CP thinks you are a scamming and your military boss thinks you are a slacker. So why take it on? Most guys do it for their country, their family, and because when you can fly a fighter or do something cool in a military plane and get to fly an airliner too, its a pretty neat experience. A lot of of the anti-military/Guard backlash isn't just productivity issues, in some cases its pure jealously. Not everyone can manage two jobs effectively. I for one am grateful for those of you that do it so well….