That is a strange smelly set up. I couldn't watch. I would be gagging!
As far as the honeywagon, we camp at Darlington, SC for the NASCAR race each labor day and have been doing it for 15+ years. The honeywagon comes around sucking out campers. We have also always been concerned about tanks collapsing from it. We were talking to a worker this year that owns the company that has been doing the area we camp in since we have been going. He said he has never seen or personally heard of a tank collapsing, and like he said, if it happened, word would have probably spread fast and they would have been run out of Darlington County for good.