[tinus_hn]

That would mean if you park your car in a garage that blocks mobile coverage you’ll never be able to start it again. Sounds unlikely.

[dagmx]

Only if you rely on only the app for unlocking. Whether you think it sounds unlikely or not, it's documented and people have run into this before with the S/X when data was unavailable.

You should always keep the fob or keycard around for safety.