On SBB app it looks like you have to manually enter on your profile that you have a half fare card. The app doesn't seem to validate it and I am not sure if the actual purchase of the half fare card will get picked up on my travel profile automatically.
Since day saver passes are available a few months ahead, Can I buy the day saver passes at half fare now even though I haven't purchased the half fare card? I can then buy the half fare card much later and not encounter that cost now.
Correct. You only need to have the Half Fare Card in your possession on your travel date, so you could buy it the day of travel before boarding the first train.
Half fare tickets are always on the honor system - saver day passes, point to point tickets, as well as passes that offer a discount for having the half fare card (such as the Berner Oberland Pass, Jungfrau Pass, etc.) They don’t make you prove you have it at purchase of any of these things, they just make you show it when coming around on the train checking tickets. If you intentionally or unintentionally purchase something that requires HFC but don’t have it, you will get a fine.
This includes ticket machines while in Switzerland at the train stations. When you go to purchase a ticket you will see a half fare option. It’s honor system when you select that option, as they’re not validating at the machines.
