Rock, I don't think people realize the risk they're taking trying to use junk to keep air in their tires.
Fleets probably get away with simply rubber valves:
First, not all their E-Series have those stupid 8-"hand" hole wheels that we've had till recently. They have 4 real hand holes, so they can reach the valves without additions. And of course no wheel covers/wheel simulators.
Second, they WEAR their tires out in a much shorter time than we AGE them out. New tires get new valves, so fleet rubber valves aren't as old as ours would be.