Originally Posted by
f4free
You will not have a problem doing this, once or twice. But on if you do this 20 or 30 times, or more, you likely will get a call from Swiss once they notice that you booked 30 train segments and haven't used them. I know this as a fact.
Yes, but this was from the time when you had to be on the train you have booked (before 2006).
As you can use any train nowadays between ZRH and BSL, and not all trains in Switzerland have controllors (e.g. the regional trains Frick-Basle), it's virtually impossible to report anything. The train controllors just check if your ticket is valid, but do no longer retain or submit any data.