I mean you just know that's never happening.Is there anything keeping them from using the Tunnel to go into Switzerland? It would be the obvious option (if they want to keep the starting location). I have to say though, if they can't do that and we are looking at a 250km stage over Mortirolo, Tonale and Mendola, I wouldn't complain too much either. None of those climbs is particularly interesting (from the respective side) but that would still be an extremely hard stage.
One thing I just noticed is that all three intermediate sprints take place in the last 50km. That seems like something you would do if you fear the route will only be as planned from Bozen onwards. That might signal they already have a backup route planned and that that backup route will not go through Vinschgau. That's really just a guess though.
I presume they'd just shorten the stage, do all the travel by bus and start in like Prato dello Stelvio