Agreed, or when you're travelling, your passport .. few things are as important as that when you travel. Was on a family holiday recently and only found out it had gone missing upon check-in for the return flight.

There's a few products available like this already... http://www.hongkiat.com/blog/bluetooth-tracking-devices/

Already been done. You can get Estimote Stickies (http://estimote.com). I go their larger Beacons when the first came out to play with there SDK. Works very nice :)

It's kind of weird, seeing the same cookie cutter template that every damn startup seems to be using, except it fits like a glove.

Using Vessyl as contrast, who gives a crap if my cup has a "unique yet subtle presence on the tabletop"? Does it keep my coffee hot? Great, then it's worth at least 5 dollars to me.

For sunglasses, design is paramount. It's a fashion statement first and foremost. Even without the "gimmick" the price wouldn't seem too outlandish, but at the same time you can immediately see how it would be useful in everyday use. And you do need a gimmick in a market controlled 70% by one single incumbent (Luxottica).

Come to think of it, the typical startup design is very much an Apple-centric cargo cult -- maybe how well it fits is somehow related to how Apple-like your startup is? (That's probably overthinking it a bit...)

Hear hear!