Gou Please note that a check-in is necessary is you have an Italian ticket for regional trains (Trenord). A check-in is not necessary for EC, but you must use the selected train.
The best way to buy the ticket and make the check-in is the Trenitalia app, you can also choose another train if you are late.
If you buy the ticket on trenitalia.com, a mail will be sent with a link for the check-in.
If you buy the tickets at the ticket office in Switzerland, be sure to get all informations to make the check-in or ask for a « Arcobaleno Transfrontaliera » ticket instead of a Trenord ticket, it is valid for 4 hours without check-in.
Very complicated for a 1,50 € ticket… Not a bad idea to take the EC who is more comfortable.