That's a good point. If you see a guy driving in an adjacent vehicle, wearing earplugs or earmuff-style hearing protectors, watch out! and report it to the police, if you're up in that area.
I wonder if the targets were all on the right side of the road (relative to that direction of travel), same as the sliding door on a minivan.
Lots of mini-vans have sliding doors on both sides these days.