Let it Ride w/ 3-card bonus error- curious

About a year ago, I was in PA playing Let it Ride w an active three-card-bonus, and the dealer was clearly pretty new at the game, but was unsupervised and was making a pretty serious mistake in payouts- they would pay even money on the three card bonus bet for any high pair (i.e., didn't need to be in the player's own cards), and I believe in some cases any winning 5-card hand in the game itself (though if I recall was a bit inconsistent here). This was low limits with nickle players, but surprisingly, no one corrected the dealer for hours. They were paying correctly on the Let it Ride game itself. It was interesting to see no one raise their bets on the three card bonus either, but no one at the table said anything...I being about as ethical as I could, would simply give back any payments to the dealer that I didn't deserve as a "tip" (I was only betting $5) but I'm wondering how this situation would have changed the house edge for the combined bet...