When the mobile goes for a walk...
Anyway, I thought of a few thing that we could use in mobile phones:
1. GPS that can be enabled remotely
2. Mobile shutdown remotely
3. Mobile detonation remotely (forget it, I am just plain frustrated here. If a kid found it, I would rather s/he kept my mobile phone and enjoyed it)
For both 1 and 2 I think the International Mobile Phone body (if there is something like that) should mandate the inclusion of a single chip in every phone. Hence, the protocol is independant of the manufacturer. Once the chip is included it is essentially disabled.
If the mobile is lost then one can call a common international number and provide the IMEI to them and option 1 and/or 2. The mobile will be tracked down or will shut off permanently.
Currently I am not sure about the GPS thing being available, but the 2nd thing seems available albeit to partial completion. The current mode, I believe, gets the service provider to disable the phone from being used on the network, but changing the SIM card would let you use the phone. A mobile shutdown doesn't let you use the phone at all: you can't switch it on.
Once the mobile is returned, these can be undone.