In my 65 years on this Earth...I've never spotted an Orphan valve stem cap anywhere. Not in a parking lot, driveway, curbside. Certainly not 'all over the landscape'. Can't be much of a problem (in Texas anyway).![]()
Next time you're at the local "big box" tire store (Discount Tire, Big O, etc), wander over in front of the shop doors and look on the ground. I was at a Town Fair Tire back in May getting my TPMS re-registered, I probably picked up at least a dozen and I quit looking.