There are some ideas, that when they come along, are so remarkably sensible that one wonders why they had never been thought of earlier; or should I say, "not in mass use".
One such item is smart luggage, a product of the "internet of things". Basically, a suitcase with a tracker.
These have been around for about a year or so and it is surprising that no one has really pushed the idea further. Suitcases that have an in-built ability to tell you when they are overweight, can be locked or unlocked from a smartphone and ... this is the good bit ... are fitted with a GPS tracker. You don't have to ask the airline where your bag is, you can tell them where it is. You could even tell them it is not on board, even before you leave.
The latest offering comes from Crests Luggage a new company currently with Kickstarter. Carbon fibre and connected. Strong enough to stand up to pretty much anything and connected, so you always know where it is. Most smart-connecetd bags are fitted with gadgetry in a way so that they shut down (or you shut them down) when you know they are on board and can (automatically) come back to life when on the ground.
We do have to assume that airlines will not have any issues with luggage that carries a GPS tracker and presumably, some sort of battery. That said, given that a laptop now has to go into the hold, I cannot see how any could complain about a small device in a suitcase, as long as the unit can be fully disabled whilst in flight, given the clear concerns about connectivity and potentially, blowing things up.
Of course, you don't need to buy the whole suitcase. Sooner or later, someone will come up with a simple device which you place in your suitcase which would be able to accomplish the most important aspect of having a connected bag - knowing where it is.