It was sent to ADSBexchange's API, not over RF. No laws were broken.

Yep, as evidenced by the "Source:Other" tag on ADSBExchange. Signals actually sent over the air would show ADS-B, TIS-B, etc, as the data source.

	▲	Scoundreller 5 hours ago \| parent \| next [-]
		It’s only “other” at the very last point. Go earlier in the track and it shows as “ADS-B”, but every historical real flight in this plane is MLAT (it doesn’t broadcast its precise position but it can be inferred from receivers)
	▲	jjwiseman 5 hours ago \| parent \| prev [-]
		That's not true. And if you click almost anywhere else on the spoofed track it will show as Source: ADS-B.