That's very common with Microsoft products too. Their vendors get to use @microsoft.com emails (distinguishable by an extra "v") so they frequently pose as "auditors" to pressure businesses into buying licenses.

It's a grey area because a business with all licenses in order would not care either way, but software being what it is it's hard to stay compliant all the time even if you try, and that's when the vultures descend.

For example say you appoint a new CTO and they realize your company of 200 PCs uses pirate Office copies, so they buy 200 genuine licenses, but they're cut short of actually installing the matching Office version because Office is a piece of malware-acting crap and is actually very hard to completely purge from a domain install. So they end up holding correct licenses but using technically pirated versions. This is where a genuine audit would not care (you paid for the newer version and are using the older, crappier version; due to their fault, I might add? you do you Microsoft got paid) — but an unscrupulous vendor would try to scare you into paying more to "fix it".