We all know the obvious things that can betray concealment: shirt lifting and becoming totally uncovered, printing or even having the weapon fall out of place and hit the floor (I don't many in this group have suffered the last one). But there are other concealment faux pas that are not quite as obvious and can only be learned through experience or training. I am hoping the group could share some of their often-not-considered points in this regard.
I'll start: concealment compromised by banging into something with the holstered weapon - that clank sound that can only come from one hard object hitting another. I do this occasionally going through a door, so I've become a little more mindful of it.
What else do we need to remain mindful of?