here in the Netherlands slingshots are almost completely illegal, i think there is an exception for weak bait-casting slingshots, but that won't help me. tho they are illegal, a friend of mine works as a police officer and he said that they won't do anything unless you shoot people or game, or maybe if you are shooting in the middle of the street.
I gave my WiiShot to a friend, two days later he had it in his backpack with some 12mm steelballs. The police controled him because he was drunk and couldn' t walk staight, they took the slingshot from him but not the ammo <img src="http://illiweb.com/fa/i/smiles/icon_scratch.png" alt="scratch" longdesc="33"> . He was not shooting. I know a policeman who works in the investigation section, i gave him one of my slingshots and he took it to his colleagues from the balistic and asked. Slingshots are illegal here unless they are really weak. If you shoot in a safe area( no people, no animals, no cars, etc..) they, maybe, will leave you alone. It depends on the police officer who controled you.
i've traded 4 times so far, 3 in and out, the 4th one inside the NL, and i haven't had any troubles, so i think it'll be okay, but there allways is a change they check youtmr package and than it's gone, it's a risk you've got to take
I make, sell and trade blowpipes (a misdomeanor where I live) and I have had officers ask to purchase them. As was said earlier it all depends on the officer you end up talking to. Most will not give half a care as long as you are not doing anything "stupid".