From personal experience working with the Swedish Rescue Drone initiative, sensitive data captured during SAR might fall under GDPR. Some groups coordinating SAR operations request complete control over image data captured during flights, and in some cases for good reason. For instance, if the search is for an animal, providing the caretakers of that animal with imagery data may make them rush out on location to capture the animal. For a dog, for instance, that has been missing for a few days their behaviour is very much polarized towards the flight response. It may be that the person missing may not want to be found. It may be that the person notifying authorities may want to find the missing person for reasons they dont communicate. There are all kinds of reasons for why data from SAR operations should not be made public.

That being said, drone use in the field is extremely useful in many SAR situations, and is often managed by volunteers that go out with machines of varying quality. Some show up with a DJI-platform equipped with thermal and optical cameras, others with sub 250g fpv drones. In some environments, simply having the altitude offers an effective enough leverage to use drones in the cheaper end of the spectrum. Flight time matters a lot.

With respect to sensor types, having access to thermal information is invaluable in some cases, and in others completely useless. It ofc depends on the thermal difference between the object you are searching for and its surroundings. In all cases, it is very expensive relative to optical information.

Anyone with decent electronics knowledge can put together a drone kit for around 150 bucks. Building a thermal camera without shelling out a decent sum of cash, on the other hand..