In theory, but since this attack has to happen at the time of pairing and leaves evidence--the key you are trying to pair doesn't work afterward--I don't think this is a realistic concern.

>In theory, but since this attack has to happen at the time of pairing and leaves evidence--the key you are trying to pair doesn't work afterward-

You're assuming the goal is to discretely enter the vehicle and leave no trace. If we consider the Kia challenge [https://en.wikipedia.org/wiki/Kia_Challenge] then the goal is to take possession of the vehicle in an immediate and opportunistic fashion. If the possession fails and the key FOB now stops working, whatever, not the thiefs care. If the possession works, now there's a sweet car to abuse. Or, in the case of a crime syndicate, a sweet car to take to the chop shop.

This type of attack is not to mention a simple relay attack. If radio waves of a home (say near the front door, where the keys are stored) are relayed to another location (the car, 30 feet away), then the exact crypto and protocol is irrelevant, the car "sees" the real life actual FOB as nearby. That's another attack used in the wild.