I suggest that anyone considering sharing a personal device with work activity (other than basic phone calls and messaging, e.g. "I'll be in late") think twice. Comes a security concern or conflict, someone's probably going to want access to the whole thing. If you want me to do "your work" on a phone -- particularly as an employee as opposed to as an independent contractor utilizing their own resources as defined in…
Would secure-wiping the phone if involved in a legal discovery process be considered destruction of evidence?
Does your advice apply when you're only using, say Exchange, as your only entry point (e.g. on iOS devices?) - in this case, all discovery can be done server-side.
I find it hard pressed to think this issue hasn't been covered more rigorously.