Several times over the years I have been in hotels when fire alarms have gone off in the middle of the night and everyone has to trek down to the lobby. It is pretty obvious that people throw on whatever clothes are convenient.
One night the rest of us had been in the lobby for a few minutes when the stair door burst open and a fat guy (another fat guy, not me) stumbled into the lobby in his boxer shorts. Every one was embarrassed for him. A hotel employee grabbed him a sheet and we all survived the night.