I need a little more details from the OP.
We have had, in my reserve platoon, members who have joined and immediately started to publicly identify themselves as MPs to peers and friends. Imagine sitting in a crim class and having some below average guy spouting off:"In my experience/job as an MP..." All the while the guy barely got sworn in. Once we hear about this, they get some counseling. Mind you, recruits are warned at the start that if they wanted to talk about it they are supposed to refer to themselves as recruits in an MP unit. Some people are slow learners.
To be fair, I do love being a reserve MP and I am proud of it. Since a lot of people somehow get the idea that I am either military or LEO (dunno, must be the haircut or something

) it does come up quite a bit. I love doing PR and selling people on the CF and the job. If I can steer someone into a rewarding part or full time occupation in the CF, it makes me happy.
But yeah, when someones whole sense of self and belonging rest with their short time in the military, it usually is a sign of deeper social issues. We really need to be careful about who we recruit. Which makes the MPAC mandatory for the reserves to stay in a real fucking good idea in my not so humble opinion. Some people can make a great contribution to Canada, just not wearing the red beret.
So, to wrap this up: Tell your acquaintance to cease and desist, for his own good. If he does not, feel free to send me a private message with his name and general location and I will make sure someone has a more direct conversation with him. Nothing career ending, just some mentoring.
Regards,