I think making sure the dogs are watched at all times, with or without reports of problems, should be standard practice. Just as a lot of us won't leave our dogs outside alone, dogs shouldn't be left alone at shows. If the handler isn't there, then imo, an associate should be. I honestly couldn't imagine leaving Ellie unattended at a place like that. When in public, one of us has our eyes or hands on her at all times. I wouldn't feel safe any other way.
And if the food or water was left unwatched, I'd be changing it. I'm probably oversimplifying it because I don't show and don't know everythin that goes into it, but I have attended before and walked through the benching area. It just does not seem like a safe place to even turn your back on your dog(s). Way too many people around...