If that’s something you are worried about, don’t choose that option.

Is there a person on this planet where an unexpected hospital visit could not happen?

I think a wipe is not necessarily that much of an issue.

Some people lose or get their phone broken and start from a blank one on a regular basis.

In my case the only things that matter to me are synchronised through syncthing and radicale (a carddav/caldav server).

Wrong question. It's not about the chance of having a wipe. But if the having the wipe is worth happening on some false positives.

Someone may want that behavior if they were intentionally injured and kept from their phone for 3 days. The perpetrators will eventually get past the hospital security. Contents should be backed up in a safe place either way, possibly in a place that someone that cares about them may access it.