Just managing expectations. A look around the interweb will show it's exceptionally difficult to get compensation from operators unless the loss is clearly through negligence. Theft by a 3rd party is not the operator's fault (unless we are talking about a secure parking facility, gated, patrolled and enclosed) so possibly the best one can hope for is cooperation by supplying any video footage. Even this is thin help as the Police are not likely to act unless the images clearly identify the miscreants.
Case in point, we just two days ago had a CAT theft (the second in as many months) from our car park at work (B&Q) the van was caught on CCTV but the reg plate was too dirty to read, Police just noted the case and supplied a reference number for the insurers.
Apart from wiring the car to the mains supply I'm not sure one can stop these scum 😟