My biggest concern if I let someone borrow my phone in a busy public space is that they will run off with it. Perhaps the guest mode should primarily be a mean

My biggest concern if I let someone borrow my phone in a busy public space is that they will run off with it. Perhaps the guest mode should primarily be a means of preventing a thief from doing anything meaningful with a stolen phone. It should probably restrict the 'guest' to only using the phone mode and prevent the phone from being placed into airplane mode so that if it is stolen it can more likely be tracked and recovered.