I'm guessing it's because the key has to be present for a relay (not replay) attack, so it's analogous to the way "card present" shifts some of the liability in

I'm guessing it's because the key has to be present for a relay (not replay) attack, so it's analogous to the way "card present" shifts some of the liability in payment card fraud? Pretty wild that the authorized user should know to protect against key fob relays though. Fun fact: they usually go to sleep (i.e., way more battery life) based on an accelerometer detecting no motion, because legitimate use would always be hand-held. To take advantage, put it on a table or hook (but not too close to your front door, perhaps) instead of keeping it in your pocket while home.