Ive had mixed results with wedges. The door sill on many of the rooms is pretty tall and the wedge can only get so close to the door so when its opened it hits the wedge pretty high and sometimes doesn't hold. You could almost squeeze between the door and the jam after the wedge finally took hold. But better than nothing.

Masterlock makes a retractable door security bar if you have the space in your luggage. Lowes sells them. They pretty much lock a door down.