I think there are lots of things that need looking at. If the law accomodated traveller types more sensibly, we'd create less of a rod for our own backs. So the law should provide for more traveller sites.Whatever is needed, and rigorous application of them.
Equally, when they decide to do what they do best - park in places they are not welcome, steal stuff and leave a total mess behind, then the law should be able to deal with them properly. And this includes the police who sometimes simply leave these communites to their own devices even when they should be stepping in.