With the utmost respect, parts of this story are unlikely and other parts inaccurate.
Surely not all stolen cars follow this pathway Peter, particularly W113’s.
Secondly, as Mike points out, Air tags only need a brief passing iPhone, just once, and they will locate the exact geolocation of where the car entered the container, or other such faraday cage. It is highly likely one of the car thief’s is carrying an iPhone, so voila, an exact location is mapped and tracked (last location seen).
The battery lasts for over a year in my experience, almost two, so it would need to be an incredibly patient thief to wait that long to offload the stolen goods.
Perhaps I am wrong, but given the thief has no idea that it is being tracked by a hidden Air tag, I have a high level of confidence I am not. I continue to strongly recommend every one has one in their Pagoda, what have you got to lose?
** I have no conflicts of interest with Apple, either stock or employment.