An Apple iOS Idea: Proximity Links Between Devices

Establish a spatial link between iPads and iPhones.

Just this week I heard of two more people forgetting their iPads. One was left on a plane; gone forever, and the second was left in a hotel room, but luckily was recovered after a breathless drive back across the city. What about adding a feature allowing people to establish a temporary spatial link between their iPad and their iPhone? That could reduce in the number of iPads left in hotel rooms, conference rooms, planes and taxis in the first place.

This would work by allowing you to define a minimum separation distance between their two devices. Then place a notification alert on top of that. For example:
Warn me if <"iPad Name"> is more than <"10 metres"> away from this iPhone in the next <"6 hours">.
Ideally, both the class of notification and its intensity would escalate as you moved further away from the forgotten device in question.

This could serve as an early warning system, preventing many lost iPads. It would compliment the Find My iPhone/iPad feature which is used *after* any loss. My assumptions here are that a significant number of iPad owners also carry iPhones and that such people are most likely to still possess their iPhone in scenarios where they have left their iPad behind.

An additional feature would be the option to dismiss the notification alert for a set amount of time:
Activate again in <"12 hours">.
This would address scenarios such as leaving the house without your iPad on a day when you are intentionally leaving it behind.

UPDATE
Two weeks later, I have come across the Zomm Wireless Leash. A hardware solution to aspects of this problem, but one requiring you to carry an additional accessory. (Sourced via the Unofficial Apple Weblog.)