Our ideas are pretty much valid if the software is to be permitted at one site. But I am remembering back to when I sold my stuff all over the country. I had to make each installation (site license) unique, so, not knowing any other way to accomplish it, I serialized every installation and added an internal value for each .VLX compiled separately for each client. Then I built a function to mathematically morph the serial number into a long hex code that I would e-mail the primary contact to use as a password to enable the code to run. Once the password was correctly entered, the code would write a value into the registry so it could be run over and over without requiring the password again. Of course I also built in a 30-day trial period so that unauthorized users could do a taste test.
It was actually more complicated than that because I was selling individual programs that were all in the same .VLX. If there were any value for it these days, I would sell the whole package, and for a lot less money.
Now if you want to password protect each seat, that would have to involve something like using the MAC address, but how do you obtain that without the client knowing. I mean I haven't spent any time looking how but I think I would have to have the installation secretly e-mail me the MAC address and computer name, which I could morph into a hex password and e-mail it back. But all that seems stupid since you can get most anything you want these days, even if it didn't exist, from the forum freeware drive-thru. 😕