Sorry for this basic question but I can find no clear confirmation elsewhere. We (family of x4 people) are travelling from Geneva airport to Zermatt on 9th March & returning on 16th. Last year we made the same journey and purchased the supersaver tickets on line. On the outward journey we jumped on the first train we could & not the one specified on the ticket - the ticket conductor didn’t even question this. On the return journey the Conductor (charmless man) told me the ticket was not valid for the train we were on and charged me for x4 full tickets (i.e. not the CHF difference between what I had already paid and the new tickets). This year I want to prebook tickets but do not know which train we will get. Can you advise what ticket I should buy with the flexibility to not be on a specific train but any train that day? There are so many different variations and it isn’t clear which is the right option. Thank you for your help.