Well for one, the pharmacy isn't moving.
Can you now envision a conversation between this passenger and the pharmacy clerk:
"I found this phone in some car"
"What do you want me to do about it?"
"Hold on to it until some guy I don't know comes to claim it?"
"We don't want this personal property! Go away!"
[Waymo car is gone now]
[Passenger absconds with phone or throws it away]
[Owner is no longer able to track or retrieve phone]
And it's not that crazy to leave lost property with a nearby business (presumably a trusted one)- sure they could say no but then you could just find another way to return the device.
Also why would you not be able to track it any more if they left it at the pharmacy, it's not like the Find My Device feature only works in Waymos. I guess you just mean due to the sequencing of wiping before noticing the text message?
Tell me more about how I somehow gave consent to that. Also, tell me more about how a stranger holding a random found device authenticates a caller as the owner of said device.
> I would say that moving the phone from the place I left it would promote it from "lost" to "stolen".
A really key element here is that they offered to help you out by leaving it there for you, so I don't see how "stolen" would come in to it...
"I found this phone."
"Ok." takes it
You go in later "I lost my phone, do you have it here?" and they hand it to you. For particularly fastidious store clerks they may ask you to describe it before handing it over. And you likely have to wait while whoever you ask asks all the other employees if they found a phone.
It's not clear to me that letting the phone just sort of drift through the ether toward the Waymo Depot while who knows how many other passengers use the car is any better than putting the phone at some other fixed location behind at least some cursory level of security.