As someone who lives in a tourist town and whose commute involves a very popular MUP I can say I've seen similar stuff. But once the tourists have arrived I don't use the MUP until they go away again. Mostly it's not individual cyclists that are problematic. It's those rental bikes that seat 5 and the rental delta trikes that are scariest, veering wildly all over, and the sheer volume of people that makes the MUP not useful for getting somewhere expediently. Also, some of these folks must also use the streets to get around, so I take extra care near the tourist area.
You know what's scariest? They now have rental electric cars that look like these silly golf-cart like things, so these people on vacation rent them and ride up and down the streets. Since when do our public roads have to serve double-duty as a playground for tourists?