In your position I'd want to know if several or many pairs were stolen that day, which would indicate a professional theft ring. If there was a known ski theft ring operating there, I'd object to paying, especially if the rental shop knew of it, which they should certainly, and didn't give you the heads up. Sometimes police stop a pickup with 30 or 40 pairs in the back; that's how the pro thing works. Some poor or greedy person looks around for one pair, their size, of a particular brand they actually want to ski on; the pros could care less the model.
Squaw has roaming, highly visible, uniformed security all over the place, experienced guys I've seen for 10+ years on the job. They catch people time to time, though it's pretty rare here, and I appreciate their help. Conversely, a ski area with no ski check or security isn't really pulling their weight in customer service.
I can't believe the shop that much, the whole thing smells to say the least. It's their ski area, they're the locals, and they must have had this happen before or knew very well about the problem, yet did nothing about it in terms of securing their demos/rentals; weird.
Notify every ski shop, as shops may check serial numbers on skis that come through for work
As was already stated in this thread PCMR has a free check for rental skis. Personal responsibility is foreign to most Americans but your argument actually surprised me. Are you actually saying the shop stole the skis? Or they know of some organized crime ring in Park City and look the other way because it makes them money?
To the O.P. I hope the skis got taken by accident and they turn up. A friend of mine was in your exact situation a few years ago at Aspen, his skis were returned a month later and they gave him his money back.