"customer might complain about..." it's NOT a mandatory scenario and here in Europe no recall was issued, I don't know US regulations of NHTSA if might be a dangerous scenario about gas concentration in cabin.
Scenario might occour with (i.g.) Climate control ON when idle with high speed of fans.
It's for sure a real scenario when you remove emissions system and re-tune ECU (not road legal here).

I saw that the US price is $17/20 each, here in Europe I paid Eur 34,75 the pair.

If you pull the liner out the boot that covers the rear lights, about 3/4 pop screws, then you can get to these easily. Possibly worth a check. A good point to collect moisture too if they aren't closing correctly, as I found.

Hmm, I wonder if this might alleviate my interior frost in the winter.

My thoughts also.