True story. I stayed at a local hotel a couple nights about a year ago.A pretty large chain, couple hundred rooms, indoor/outdoor pool sauna ect., ALL night long, everyhalf-hour or so, like clock work, starting at about 2:00 am and ending at 6:00 am, :the room next to me would flush the toilet about 5 times in a row and I'd smell hydrochloric acid or whatever smell that puts off, bad! I tried to investigate, and I realized there was no room next to me! Tthe flyers had the layout of the whole hotel and there was just no door there and the next door was 2 doors worth, down the hall. In the whole hotel it was the only place that wasn't on a modular type measurement between the doors. They were running a tube down the toilet to exhaust the fumes, is my theory. I'm convinced it's an inside operation going on there. Only someone staying up all night every night and happening to be in the next room would have ever noticed.