Hello DFG
Usually when you travel abroad DIY, yes, you are responsible for your travel plans yourself. Otherwise, you have to book a guided tour.
The timetable does not offer fake connections or connections that suddenly disappear. However, it is always good to check the timetable again shortly before travel.
Commuters often do save their trips in the SBB Mobile app, so they get notified if a service is disrupted on their route.
If, in the unlikely event, a connection becomes unavailable, you can simply take a connection that gets you to the end destination, no matter the routing.
Kind regards,
Roland