Can we no longer lock doors on community lots?

It's not and has never been possible to lock doors on community lots if they are not owned. The club locking option is fussy, because you first need to make a club and I find that to much bother just to lock a door and the number of club members is rather limited. Sims don't visit "hotel" rooms unless you add a TV or some other highly attractive gameplay object. As long as you have just the bed and basic hotel room furniture, your sim can spend the night undisturbed.