Yea I don't think lodging was ever a requirement. As long as you arrived the same day you were good to go. I wish all local towns would make this a policy too.. Arrive to any major ski/board city and be able to ride for free the day of arrival.
Last year Frontier Airlines had a deal like this good for a lift ticket at Copper. You could use your boarding pass up to 3 days after you arrived in Denver But there where black out dates and I could not take advantage of it.
I did it last year.
You first apply online and fill out the Park City promo application. You then receive a "Park City Quick Start Redemption Voucher".
If I remember correctly, you then present the approved voucher and the boarding pass at the window to get the free pass.
I don't recall any blackout dates or having to stay at a Park City hotel...