(This story is repeated elsewhere, so stop me if you've already heard it.)
I watched IBR riders come in to the checkpoint at Johnson City in 2015. The official checker-inner said this, very quietly, to each rider: "Is your kickstand down? Is it ALL THE WAY down?"
From that moment, I've always looked at my sidestand whenever I lower it.
And, for the record ... I dropped mine in traffic when I needed to get something out of my armored pants pocket. I threw down the sidestand at a red light and watched; it went all the way down. I dismounted, then realized we were on a downhill slope that was steep enough for the FJR to creep forward and retract the sidestand all on her own.
The guy in front watched it happen in his mirror, and jumped out to help me get her picked up. We did, and everybody was ready to go when the light turned green.
Embarrassing. (Since I do not have crash bars, she didn't roll over and break my mirror stays.)