Though shrinking the admit size is another well worn tactic, as it's the easiest way to increase how "selective" you are which is another major ranking element, plus it helps you more cheaply achieve smaller average class sizes, though of course you're forgoing some revenue to get there.
If not accepted for any of them, there's a follow-up matchmaking service (called 'clearing' in the UK) to help find an unallocated spot.
Based on a conversation with my nephew who applied to a double-digit number of colleges this past year, the application fees are apparently more the exception than the rule these days.
You can if you admit on objective metrics. If you only take people who are 215 pounds or above, you can fairly claim to reject everyone lighter than that, regardless of whether they apply.
It's a fantastically anti-consumer market they've managed to create.