A small child nicked my keys and dropped them somewhere in a large field. A detector was cheaper than a new electronic key for my car.
That is hilarious and quite interesting!
Using a metal detector here in Sweden requires a license from the government.
This is to prevent scavaging archeological artifacts.
This is true, they have however debated the issue and might loosen the restrictions:
https://www.riksdagen.se/sv/dokument-och-lagar/dokument/motion/forenkla-regelverket-for-anvandandet-av_H902681/
TL;DR and for non-swedes: the suggestion argues that hobbyists should be allowed to use metal detectors more freely. The motion was initally approved by Riksdagen but later voted against as there already work in progress on matter of simplifying the rules regarding metal detectors. So change might come, hopefully sooner than later
They might as well just require a license for people to go searching for things. And what if the artifact is made of wood?
Untill someone makes a wood detector I don't think they are worried about it.
The point is that a metal detector is specifically made to find stuff easier, and significantly cuts down on manpower needed to find stuff, increasing the risk of scavanging.
Do they have a license to stop dogs from being trained on the scent of certain materials?
Nope, not to my knowledge.
I have never heard about that being a problem or even a thing.