On April 21st I played on a Team Fortress 2fort server with a user by the name of snipi. He gave me a Mann Co. Crate Key, which I have since used to open one of the many Mann Co. Crates in my possession.
It's been brought to my attention that this user's account has been VAC-banned within about the past twenty-four to forty-eight hours. There's a message on the user's profile that states:
This account wasn't used from the original owner (Snipi) since ages... So I decided to play a bit with it
and I had a good run but VAC noticed that and it is time for a different account! ;)
I even left Snipi a little gift (a VAC Ban)!
I am such a nice person... ain't I?
Yours sincerely, R3BORN"
My concern is that, by accepting the Mann Co. Crate Key, I may have opened a door for whoever hacked this user's account to access my own. I'm not well-versed in computer technology/coding, so I'm not sure if the user could have somehow corrupted the trade (it was completed through the server) and used the Mann Co. Key as a back-door of sorts to access my account at a later point.
It doesn't appear that my account has been compromised at this point. I've not noticed a change in my Steam Wallet funds, my Items, my Profile, my Library, or my friends List. But if anyone can give me some assurance that I'm just thinking catastrophically here I'd be most appreciative. Thanks for your time.