I mean Wario isn't rude enough to do that but if he had no money... Know what he'd probably get his dragon had on and burn people for money if he was really broke and he had no other options. Shaking people? Wario has no respect for life. The Brawl cutscene where Wario turned Ness into a trophy indicates he would enjoy it too unless you guys think his personality is different from Brawl's representation of him.
Is Wario nice enough to stop a shooting? Yes he would because he'd expect money as a reward or just steal the weapon and sell it.
Wario would go into a school wearing a black trenchcoat and pumped-up-kicks, then he would reach into his backpack for a Kalashnikov and start shooting