Another advantage of thin clients is that remote users can't get booted off by a student turning off the workstation you are logged into.

Since Apple allowed employees to go outside with prototypes they probably accepted the risk of losing these phones. I doubt they will fire him, more likely he will be given a poor performance review for not protecting company secrets. Accidents happen, and if a large attractive employer like Apple fired someone for making a mistake while testing a device in the field, then no one would ever volunteer to test these devices (which is absolutely necessary).