that may only apply to public land, and/or "scheduled sites". Might not apply to private land (farmer's fields with permission, etc....). There's been Italian hunters posting finds over the years, and ..... not sure that they're trotting down to the "competent authorities" with each 71+ yr. old coin.
The same could be said of USA sites too, if someone worried long enough and hard enough about ARPA (a 50+ yr. old law we have here). There's actually been purists archies who do indeed believe this filters down to even state, county, and city level lands. So in other words: If you ask enough purist archie bureaucrats, I'm sure you can find some that will say you can't even detect your own front yard.