Yeah, I wouldn't trust company MDM on a personal device at all. Best case is that someone with an itchy trigger finger wipes your phone. Worst case you've got someone deciding to poke around your personal device for shits and giggles.

Ironically, a week before I left one of these companies, they remotely wiped my work laptop. Someone got the memo wrong, and I spent the better part of my remaining time with them trying to get access to all the various systems so I could complete one bug ticket. I hate to imagine what would have happened if I had given them access to my personal phone.