After 9/11 there was a rash of firefighter impersonators around here, and it amazed me the lengths that some would go to play firefighter.
One time I was at a bar with friends after playing in a softball tournament in a neighboring town when I saw a tshirt with my department's name on it. Looking closer it even had my engine company number on it. Two problems were we never had tshirts designed like that, and the dude wearing it had a full beard. (Firefighters are typically clean shaven in order to get a seal on their SCBA masks. While possible to get a seal with a beard, it is difficult and people with beards tend to lose them easier than those without)
I approached the guy, told him I liked the shirt and asked him innocently where he got it. He, in an arrogant tone, said "I'm a firefighter there and they issue us these shirts, They don't hand them out to just anybody." At that point I decided to have some fun with this mutt. I told him that ever since 9/11 I had seriously been considering a career in the fire service, that I had always been interested but now seemed like a good time to get involved and do my part. He started talking up a bunch of BS, didn't even have a clue how the hiring process worked or anything about the department. I talked to him for about 15 minutes before I asked when he worked again, that I would like to know more but didn't want to impose on any more of his time just then. He said "Monday is my next shift." and I set the hook. I said "Monday works great for me too." I then pulled out my wallet and flipped over to my ID and said "I'll already be on duty at Engine 12." He started sputtering, stammering, and finally got belligerent with me and tried to goad me into a fight, pushing e several times. The bartender had evidently been listening, and he knew some of the people I was with (brother firefighters with several different agencies) since they were regulars and figured out pretty quick this guy was a fraud and I was exposing him. The bartender kicked him out and told him to never come back. After the bouncers escorted him out, the bartender told me the guy had been in several times and had been trying to use the "I'm a firefighter" line to hit on numerous women.
I reported the incident to my command staff, but other than "Jeff" we didn't have a name for the mutt. My Battalion Chief at the time was an old school fireman. He said "I would have kicked his ass and stripped that shirt off him."