Here is an idea. As it is ONLY the battery that sometimes catches fire why not have a system for batteries that is similar to car rental? Another way is to discharge the battery beforehand as it appears that fully-charged batteries that are packed with power, present the greatest risk.
Of course there are Jobsworths everywhere, for example a scuba diver informed me that "they" will not allow aqualung cylinders on the bus even when the pillar-valve is removed! The largest Jobsworth's exhibit I've ever seen was at Heathrow. FOUR pallets has been set out in a square, The pallets were piled high with "contraband" such as drill bits, metal combs, nose-hair-scissors, tin-openers, nail files and anything made from metal that might possibly come in handy for hijacking a plane. The exhibit which was about four feet high was a veritable work of art that really deserved to be in a museum.