If you think that prevents this, you're wrong. My company did the same thing, and when they announced RTO, people pointed out that they only had enough capacity for maybe 80% of the employees to fit. Management's response? "I've seen empty desks in (other unrelated building on the other side of campus), I'm sure we'll make it work".
Don't think that something silly like "physical space" or "maximum occupancy limits" will get in the way of a stupid decision.