Can't answer about the DOT making them move the exhaust, but on our Dynasty it is right under the dinette on the street side and with the window open eating dinner we don't smell a thing.
On my aunt/uncles Beaver Marquis it was located at the rear of the coach (bedroom) and they never had an issue with exhaust either.
Think about the coaches with their water heaters located back under the bed near the bedroom windows, there is just as much potential for CO2 gasses there as well. There are quite a few with the water heaters and/or furnaces located near bedroom windows.
Just a thought.
Mike.