Hello KMB
Yes, sbb.ch as well as the Berner Oberland Pass organisation are the official sellers.
Working as a ticket inspector, I can tell you about tourists that I regularly meet on the trains; tourists purchase travel passes from some doubtful websites, being attracted to their cheap prices and thinking it is a bargain. They purchase their travel passes, they receive the travel passes, they travel to Switzerland, and when they show the travel passes to the ticket inspector and the inspector scans the QR code, they are no longer valid as the money has been refunded meanwhile.
What happens, these doubtful websites sell you a travel pass for a little less, claim your money, do purchase official travel passes in your name from SBB, send you the official tickets issued by SBB, then suddenly ask SBB - behind your back - for a refund; SBB is refunding the travel passes expecting it is you claiming the refund. All the money is back with the doubtful website operator.
You do not have a clue of what has been happened in the background and happily travel to Switzerland thinking you travel for little money. And then, during the first ticket control, the ticket inspector says: sorry, not valid. And then you have a hard time explaining it was not your intention to cheat by using cancelled passes. It can get you into a very unpleasant situation, involving even the police (we are forced to call them in that situation), and high costs. And instead you were enjoying the beautiful countryside, you are going to spend your day in a stuffy police office explaining there was actually a ticket fraud. And all, for a few bucks less than the official travel pass cost from an official point of sales.
I do not want to scare you, definitely, not. But, I want to share my professional experience with you. There are promotions and special offers, indeed, but look at their URL, check the fine print. If there is a small doubt, stay clear from that offer.
Kind regards,
Roland
