I would like to depart Paris on Friday via the RER to CDG. I usually take the elevator from rue Xavier Privas (St-Michel) right to the train platform since I've got luggage and don't have to do stairs, plus it's cheap, fast and right near my apt. Only problem is the single validation machine is not working. The door, however, is open and people are just walking through. If I am unable to get my ticket validated but get on the train anyway, does anyone know if I am just left to luck, a smile and a little charm to avoid the consequences of an invalidated ticket? I am well aware of the various Plan B's for getting to the airport. Opinions?