South Carolina scored its 11th run vs LSU on a 10th inning catcher's interference and balk call, umpires ruling that the catcher illegally interfered with the batter by prematurely jumping on home plate prior to a pitch arriving during which a runner attempted to steal home.
NCAA Rule 8-3-p states, "If, on an attempted squeeze play or steal of home plate, the catcher steps on or in front of home plate without possession of the ball or touches the batter or the bat, the pitcher shall be charged with a balk and the catcher with interference." The equivalent rules throughout the levels are OBR 6.01(g) and NFHS 8-1-1e.1.
Throughout the 15-minute delay as a result of the umpire's call and subsequent LSU protest (yes, college still has protests, no protesting a judgment call still should result in denial), the broadcast focused on the catcher's positioning at home, claiming he was not "on or in front" of home plate.
Rather than engage too much with this argument, we instead turn to a different rule that brings us to the same conclusion. NCAA 8-2-e-2 discusses catcher's interference that occurs when any runner is attempting to steal a base: "[A stealing runner at any base] shall be awarded the base the runner is attempting to reach."
As for the balk component, R3 is awarded home plate either via balk or because of attempting to steal the base when catcher's interference occurs while R1 gets second base because the batter becoming a runner on the catcher's interference award forces R1 to advance.
For reference, defensive interference is defined as "an act by a fielder (usually the catcher) that hinders or prevents a batter from hitting a pitch" and replays indicate this catcher jumped in front of the batter, blocking his access to home plate (and the pitch) prior to the pitch's arrival. The batter had no free choice at this point to swing or not swing (and before arguing the batter must swing, think about it...requiring the batter swing here means catchers will get seriously injured...).
After the play as LSU set up to appeal R3's missed base touch of home plate (ruled "safe"/no miss by the umpire), R2 ran toward third base in an attempt to draw a throw, since all appeals must occur during a live ball (in OBR/NCAA) and be made before any subsequent pitch, play, attempted play.
Drawing a throw to third would thus be a play or attempted play and close the window on the appeal on old R3 at home. Nonetheless, the umpire ruled R3 safe because even though the runner didn't touch home plate during the initial play, the interference and obstruction rules allow umpires to award base touches in order to nullify the act of interference or obstruction.
Video as follows: