My not-a-lawyer guess is that the old TOS applies to old versions of Unity - but if you update to the new version, you're stuck with the new TOS. (And Unity is not going to bother telling people that existing, non-updated games are exempt from this whole fiasco.)
I suspect Unity is actually planning to totally ignore everything not distributed through a trackable service, but they don't want to announce that to the public, because then dev companies would be actively looking for ways to dodge their install tracking.