Very little is needed.
Once the criminals know they can’t block roads or destroy priceless artifacts they’ll stop completely.
We’re dealing with lunatics and cowards here.
A few examples are all that’s needed.
Discussion
As with children, I think it’s important to show that we’re not going to tolerate this behaviour. I see too many people simply accepting, or at least showing mild annoyance (even if they’re absolutely furious).
It doesn’t help though. I feel like arresting them doesn’t quite help either. I think society needs to show them how they feel about them. It should be made personal.