According to Apple, the system should not lock if plugged into vehicle power and actively navigating. Upon further investigation, we have a couple things that may be throwing a monkey wrench into the mix:
1) User may be using Google Maps instead of Apple
2) User may not be plugged into power.
So I'm allowing tablets to have auto-lock set to 'Never' and Phones I'm requiring lock in 5 minutes. I think y'all are right, this is more an iOS issue than Meraki. And no, there's no way I'm jail breaking our phones. 😄