I don't keep one physically on me, I do have one in my "BOB" that is always in the car or with me if I'm out and about.
......... This will likely change with my 31's though. They seem somewhat prone to loosening screws.
I personally have not had a problem. Mine came locktighted. I was referring to what others have posted.Have you tried doing a DEEP clean on the screws / posts? I find that if something is consistently coming loose, more then likely something is in the threads. I'll spray both the screws and posts with rubbing alcohol and clean with a Q-Tip and rag. Let them airdry for a little bit and re-assemble. Should hopefully solve your issue.