The industry needs to tackle the issue of baggage and ground evacuations. The evacuation demo required during certification is (
AFAIK) completed with all the overheads closed. Opening an overhead could impede the escape route for someone else, having large bags at the doorways certainly slows things up, and bags have been responsible for serious pax injuries on and around the slides.
I have been advocating central locking of overheads for several years now, as it would provide the only guaranteed means of stopping pax retrieving bags. The argument about in-flight fires is valid, which is why I would link operation to the evacuation alarm. That way, you only lock the overheads on the ground when starting an evacuation. Alternatively, you could opt for locking at the 'crew to stations' point or as part of the SOP during an emergency return when an evacuation seems probable.