From playing b-ball in the past, one can tell a rim is tight when warming up and often by the sound when a ball hits the rim, or actually lack of sound. The ball will just fly off a tight rim and doesn't have much give. Watch the high bounces off the rim and rebounding. When a rim is loose and gives a bit more a ball can die on it a little better. Adjustments can be made either way.
Actually, in these early tourney games, watch how the bounces off the rim messes up the timing of the rebounding when the players try to time their jumps.