I'd second that. If someone is circumventing your licensing checks then they're not a customer, but on the plus side they're effectively the same as a free plan

I'd second that. If someone is circumventing your licensing checks then they're not a customer, but on the plus side they're effectively the same as a free plan user (with zero support) and maybe in their next job they'll recommend using your tool and getting a real license, or maybe they'll get tired of hacking each update and just buy a license. I can see the idea that the OP is suggesting but decades of keygens and hacking have taught us that if someone really wants to use your software without paying, then they will. I've seen people craft elaborate ways around my own software licensing check when the actual "hack" is jaw droppingly simple (and is all on github), the point is that the people you need to concern yourself with are the people who will pay for a license.