I think @e6bflyer had a really good post on opportunity costs, may have mistaken on who wrote the post. While that post applied to getting out vs. staying in, I think it also has some merit talking about how much you can make just flying the line versus going on a mobilization. IDK, I think it is an easier decision now that first year pay has gone up significantly at AA (from $40 an hour to $75!), and that is very similar to Delta, UA, SWA and FEDEX. Makes it easier to survive the pay disparity after getting out of the military. But the system seems ideally designed for those that are drilling once a month, especially with how a junior guy can exploit the system to get weekends off, and arrange their schedule by dropping mil leave. I have been pretty impressed with how some of my peers have taken advantage of the system to get the most pay and best quality of life. Then again, they also commute, so their priority is reducing time at the crashpad.
Whereas mine is maximizing my time off hanging out at the beach or pool. 
I understand that, and sure go on MOB, take those orders. But be aware that you may be extending your probation one for one. And be aware that you could be setting yourself up for a trip back through the school house (training risks, etc). It's naïve to think that if the company wanted to fire you during probation since someone is being a douche nozzle that they couldn't do it. My point being, you are an at will employee, understand the target you may or may not be putting on yourself during your probation. The guy or gal that gets hired, goes through initial training, doesn't get consolidated, goes on 1 year MOB orders, come back clueless about company procedures and the plane they were initially trained in, goes BACK through training, and what if they hook an event? Now you opened up your whole history to being looked at. They can't fire you for the MOB, but they could let you go for other reasons, and they DO. I think we have had ~15 new hires fired this year due to training, attitude, etc... Union tries to get involved and help, but at a certain point in the process they can't help.
My over arching comment and why I weighed in, as a newhire at any of the airlines, you just won the lottery, and have a multimillion dollar job of career earnings. Where you have been hired at the fore front of what will be a sustained hiring wave that should give everyone at UA, Delta, etc a very good career (knock on wood). Minimize risks where possible to that new job and make it through probation, why extend it?
But yes, always beware of the risks no matter what you do or join. But you don't have to worry about that, you already got yours! 
