It's Always Morally Correct - It's always ok to emulate

"Except mine… I'll kill you if you emulate them."

Honestly that'd be in character for Wario. I can imagine in-universe say 18-volt downloads a ROM of one of Wario's older games (Warioware is a two decade old series now), and in response Wario tracks down 18-Volt's IP address and rather than send a court document he just barges into his house Kool-Aid Man style and demands all his money.