Most of these men and women don't expect a discount, it is offered to them from the companies in appreciation for their work. When you start running into burning buildings instead of away from them, risk getting shot responding to a domestic call, or are sent overseas to get your ass shot off, maybe you will also receive the appreciation from those companies.
Before I retired I was working for a contractor. Often I had to work with military folks that were sent here for some certain project. They were away from their families and homes. I always took them fishing in the bay or to my cabin on the weekends for a getaway. I not only didn't feel like I had to do this, but I never took a dime from any of them and they certainly never asked and sure didn't expect anything. We always had a great time and I was glad to do it. I was also thankful for their service and for the opportunity to know these people.
There are always the rare few that believe they are entitled to some form of special treatment or discount. To them I say, "Isn't this the business that you chose????"