At the end of my Swiss vacation next month, I'll be taking the train from Bern to Zurich airport. Tickets for my travel date aren't available yet, but when I check prices for some similar dates, it looks like I can save some money by getting a supersaver ticket from Bern to Zurich HB, and then paying the standard fare from Zurich HB to the airport.
Is there any reason not to do this? In some countries I'd be very comfortable playing games like this, but I have no experience with the Swiss train system, so maybe there's some reason it's disallowed there?
If I do get a split ticket, can I stay on the same train at Zurich HB (assuming that it continues on to the airport - it looks like some do and some don't - and that I'm already in possession of my ticket to the airport), or would I need to disembark and board a later train?