I think this is a relatively simple problem to solve with copyright and licenses.

It really isn't that simple.

20 years ago I was contracted by a large, very well known company in the UK to do some system testing on the latest version of an in-house developed piece of software used widely across the companies many sites. Early on, I detected a problem by accident that fell outside of the prescribed test regime, but that manifest itself when setting up the tests. With a little effort I reduced it to reproducible scenario, and reported it. Big business being what it is, they asked me for the test ideintifier that produced the problem, and when I couldn't give them one, they dismissed it as irrelevant. Luckily, bug reports weren't only sent to the IT department, but also to the Production sysadmins for sign-off. And one of them recognised some of the symptoms as being the same as a transient, but recurrant problem that had bugged production systems for the past several years and versions.

What's this got to do with your post I hear you ask. Once authorised to track down the bug, I traced it back to a rs232 comms library used by the application suite. Whilst the source code for this was 'on file', the code was actually owned and licenced from a third-party company. Actually just a one-man band, that had been brought in to develop the original system. When I suggested that it would probably take me a couple of weeks or more to understand that library sufficiently to implement a fix. And that it would then need testing. The IT department, mindful of their testing and rollout schedule stepped in with. "It's not our problem to fix it. Call in the original developer". Which they did.

It turned out that he had been paid for his original work, and the licence for the first year. But from that point forward, he had never seen a dime. That was 6 years, 3 major versions including a switch of OS (DOS to OS/2), and a myriad of minor releases. As well as a near doubling of the sites and quadrupling of the servers on which his copyrighted and licenced code ran. Had the bug not come to light and the IT dept. called him back for "service" under the original contract (despite it being long expired), he would never have known.

And that's the problem with copyright & licencing for the small business and lone programmer. It is impossible to police what a company does with the code, once your initial contract (and access) expires.

Note:There was never any suggestion that the big company deliberately set out to cheat him. It simply slipped through the cracks of their procedures and staff continuity. (He was actually overjoyed with the settlement they offered by way of compensation, without him having to take any kind of legal action. It paid off his mortgage and brought him a new car.)