I used my Ikon at Snoqualmie and Alpental (Boyne owned) last year on weekends and had to make reservations. It never showed up as "full" and I am not sure they were actually restricting numbers in any way. It seemed it was just a hoop to jump through.
Counter that to Ikon owned Crystal, which had COVID reservations for everyone and weekends filled up a month before you intended to go.