I like the idea of lockable bins, however given money & time and the inherent risks of adding more electronic devices to ageing aircraft, why not a simple key lock?. Cabin crew move down the aisle checking the bins anyway, take ten seconds to lock it too, then unlock them after reaching the gate, it would have the added bonus of keeping people in their seats until reaching the gate.
However, one floor in the plan is the floor! Many airlines now, BA and IB included, get people to put their hand luggage under the seat in front, I won’t, as it is required for my legs/feet and I refuse point blank. No way of locking that away.