The Dodgers were only selling tickets to this Yankees series if consumers also bought a ticket plan of some sort. This means that the average Dodger fan who can’t afford to go to a bunch of Dodger games could theoretically be priced out of the Yankee series altogether. In theory, the people that could then afford the higher ticket output for multiple games are less rabid about the Dodgers than those that can only attend a few games a year. If the mix of fans at Dodger Stadium changes and includes a smaller number that are willing to scream their guts out, it stands to reason that we’ll hear more cheers for the opposing team throughout the game, and we’ll also see more Dodger fans leaving early.
Second, the Yankees are by far the hottest regular season draw on the Dodgers’ schedule, so these tickets would be worth the most on Stub Hub, eBay, etc. If consumers who purchased the mini-plans felt that the total cost of the required plan was too much, it’s within reason that a certain percentage would take advantage of this increased interest and sell their NYY tickets to the highest bidder, thereby reducing their total financial output for the mini-plan they quite possibly did not want in the first place. This could then lead to even more less passionate Dodger fans, as well as more Yankee fans at the games.
I don’t have any knowledge of the Dodgers ticket-selling practices or what percentage of fans traditionally root for the visiting team at Dodger Stadium compared to this series, but I think there’s something to this.