Under Calendar > Settings > Availability I've had a 3 night minimum set . . . . Or at least I thought I did. 

Several 2 night bookings have snuck through recently, including one covering an expensive weekend day in June which it was triggered me confirming this. Called host service, turns out that this setting does not actually do anything at all, because to actually change the minimum you have to click on the current date (or whatever date in the future) and do a date range for the rest of your open calendar in order to actually set the minimum within the actual calendar blocks. 

IIRC you used to be able to set minimums for certain check in days, because my calendar block where you select dates showed "2-3" as the minimum, so maybe it migrated the old minimums based on check-in day and applied them? Seems silly that VRBO has a very easy to find setting that does literally nothing for changing the actual minimum that guests can book, because the calendar selection block overrides this. 

While I agree with the general sentiment that VRBO attracts better quality guests, their User Experience is awful. They really need to poach some talent from AirBnb, who do a much better job of making a more intuitive interface, at the expense of crappier guests. Pick your hard I guess