So you were probably happy with the 10% discount until you heard that some others were getting a larger discount. You were so unhappy that you wrote a letter of complaint. Your letter just strikes me as childish. Even more so because you actually had the nerve to ask what the Border Patrol agents were getting.

My guess is that these agents and officers are getting the discount when in uniform --- in other words, while on duty. It's a nice thing for an establishment to do for them when they're taking their "lunch break". A lot of establishments do this.