At DAL I doubt anyone would notice or care. You certainly wouldn't feel any blowback on the line. As long as your paying your share, why would it matter that you choose to not vote? The majority don't vote in elections. Union meetings with 30 pilots would be considered well attended. And even contract votes see large percentages just not bothering. Go ahead and opt-out if it makes you feel better. If you don't tell anyone, no one will know.