Personally talk to every individual participating company. Provide an endpoint that hands out a per-client hash that rotates every hour, stick it in the UDP packet, whitelist query IPs. If somebody reports spam, no problem, just clear the hash and rebuild, it's not like historic data is important here. You can even (one more hour of vibecoding) track convergence by checking how many bits of reported IPs match the existing (decaying) hash; this lets you spot outlier reporters. If somebody always reports a ton of IPs that nobody else is, they're probably a bad actor. Hell, put a ten dollar monthly fee on it, that'll already exclude 90% of trolls.

I'm pretty pro AI, but these incompetent assholes ruin it for everybody.