It feels like the recipient company did an awful lot of work in response to what was at best a fishing expedition. A serious complaint about licensing that demanded a real response would have been sent by post. It's not clear to me that scattershot LinkedIn messages deserve any response at all. The fact that the initial message lies about trying to contact him another way is another check in the "ignore this completely" column.

The same way that I wouldn't bother to fact-check a spam phone caller, why give any credence to this kind of thing?

I always assumed ppl deleted this sort of spam. It was kind of interesting to hear what happens if you indulge it.