Not too long ago I was “followed” by an outfit promoting a piece of gear you could put your RFID chip containing ski pass into (bigger resorts use RFID containing passes to expedite the process of checking your pass for validity prior to loading onto a chair). I don’t think that is a bad idea, especially for season passes. Any piece of paper, plastic, or what-have-you uniquely tied to you has the potential of leading to identity theft.
However, the folks at Ski Pass Defender seem to be more worried about the good guys than the bad guys.
Their promotional tweets, material, and efforts seem targeted at preventing your pass from being read for any other purpose than loading and this includes the resort itself in trying to gather data to better understand the ebb and flow of people as they ski during the day.
I dunno, if a ski resort can safeguard my identity from thieves and they want to use the data gathered from my ski pass RFID I am fine with that. This will allow them to better understand and plan for the days on the hill. They will have solid information from which they can setup promotionals to smooth out the noon time rush for the food spots, they can better anticipate what conditions lead to what runs being skied and can increase services to those runs, and so on.
When you are done for the day, then pull out your ski pass defender and store your pass in it then.