First, in the 10th inning of Game 1, with one out and runners on first and second base, Yankees outfielder Verdugo ran to catch Dodgers batter Shohei Ohtani's fly ball in foul territory along the left field warning track, catching the baseball before falling into the stands and attempting to throw the ball back to the field to hold the runners.
LF Umpire Chad Fairchild ruled Ohtani out on the catch and awarded runners R1 and R2 one base each pursuant to Official Baseball Rule 5.06(b)(3)(C) pertaining to catch-and-carry situations, which states, "If a fielder, after having made a legal catch, should step or fall into any out-of-play area, the ball is dead and each runner shall advance one base, without liability to be put out, from their last legally touched base at the time the fielder entered such out-of-play area."
Finally, in Game 4 in New York, RF Umpire Mark Carlson called spectator interference when a front-row fan reached over the foul fence as Dodgers outfielder Betts was attempting to catch Gleyber Torres' fly ball.
For this play, the relevant rules are found in the definitions: "Spectator interference occurs when a spectator (or an object thrown by the spectator) hinders a player’s attempt to make a play on a live ball, by going onto the playing field, or reaching out of the stands and over the playing field," and OBR 6.01(e): "When there is spectator interference with any thrown or batted ball, the ball shall be dead at the moment of interference and the umpire shall impose such penalties as in their opinion will nullify the act of interference."
Thus, to nullify the act, Torres was declared out and the fans ultimately ejected not by the umpires, but by Yankee Stadium security.
Video as follows: