Yeah, that is indeed scary, and something to be taken into account for disaster recovery planning. Off site backups of systems need to be designed so that the whole RAID array can be physically destroyed (fire, flood, theft, axe, etc) and recovery will not take a ridiculous amount of time.

The wise sysadmin mantra of "RAID is not a backup" must be kept in mind at all times.

ZFS in RAIDZ2 mode.

Unless 3 drive controllers die simultaneously, you can survive finding faults during a full rebuild.