buying them and saying you want the park never does anything walking in with a piece of paper that says I won't buy a pass unless that park is open to the public sign this saying it will be, and heres your money, that actually makes them feel somewhat morally obligated. I personally have gone there bought a pass to ride their super pipe as it was the closest to my home they told me it was open. they pulled my pass for ducking a rope to go look at it, the damn thing wasn't even built yet.
more to the point, most resorts in utah all have the same insurance provider, and in reality are on almost the same plan so if PC has it open to the public any other resort can too its not their insurance that won't let them do it. its the willingness of the resort to maintain it.