OF COURSE Kentucky gets to shoot free throws before the game starts because of this. It's impressive to see the zebras going full (apparently censored combination of referee and Kentucky) before the game even starts.
Yes, it's a rule. But in how many other games have you EVER seen it called?
More from the UK beat writer on the most petty, gift-wrapped UK way to begin a game. Slive is still probably at full mast:
So the specific rule is you can't dunk in warmups once the clock hits 20 minutes. K-State walk-on dunked at 19:58.