All the ski-passes we took home over the years are not readable for the 13.56
MHz RFID reader. According to EWcG AXESS in Ski Industry they are ISO 15693 tags which can be read at
up to 50 cm, which suggests lower radio frequencies than 13.56 MHz.
I checked tags from Portes du Soleil and Grand Massif.
In Serfaus-Fiss-Ladis one returns the card at the end of the ski
period to get the 5 euro deposit back.