Originally Posted by Track

Lots of trains in Europe are shown in the timetables requiring reservations. The only daytime trains I've ridden on that "really" required a reservation to even get on the train were the old TEE trains, but that never mattered much, and one could confidently get on if the train appeared fairly empty (sometimes the Italians required paying the reservation fee on board - it happened to me on the "Gottardo"). The Italian Eurostar trains also absolutely require a reservation, but I've seen people get on them and take an empty seat, only to be chased out by a reservation holder at the next station. I've never seen a conductor check the reservations on a Eurostar train. The German ICE "Sprinter" trains have a similar arrangement, but here I've only seen a conductor collect the higher "Sprinter" fare (which includes the reservation fee) from a presumptuous passenger. The French TGVs also require a reservation, and I've never seen anyone on a TGV without one. I haven't ridden the Switzerland-Italy express trains since Cisalpino went out of business (only locals), but in my experience Cisalpino never cared much about reservations, even outside of Switzerland. Has anyone here ridden the line lately? Do SBB and Trenitalia bar anyone without a reservation from boarding? Do they collect reservation fees on board from people who just pop up?