IDPA: It goes without saying there is always some nervous gun guy at a match with an opinion, but you have to do what he says...it's one reason some peeps don't compete..
Never heard of showing an empty chamber, usualy just holstering is considered safe.....
It is not just IDPA that has set up the triple redundant system other gun games use the same procedure, IDPA didn‘t invent it they just copied a good system. The shooter unloads and looks into the chamber to make sure it’s unloaded, then the RO looks into the chamber to make sure it’s unloaded, then the shooter lowers the slide and dry fires into the berm just incase they both missed it. If 100% safety isn’t your game, neither are any of the gun games.
FWIW ranges are almost always "cold" so a loaded pistol is a no no unless you are the shooter.