Yes they can!

I joined when I was in high school, took a semester of school off and went to training. Came back started college got a degree and up through my CFII and only came out with about 5k in debt thanks to all the incentives and bonuses (and working) offered by the guard. Yes I was sent, let me rephrase that, volunteered to go to the desert once. But I am in a fighter unit and we don't get sent over nearly as much as our heavy brethren. I also went on many other TDY's with my unit and all were voluntary including my trip to the desert. I had no problem getting through school, even graduated a semester early. Going on all those deployments and working hard paid off as my unit offered me a pilot slot which I graciously accepted .

If you have the desire to fly for the military and serve your country then go for it but if all you want to do is further your civilian career, stay away! There is far to much worked involved with military flying to do it for that reason.