If I work for a bakery, bake a cake at home, and come put it in the display cooler at work, they might have issues with that.
There’s more to that than the simple example you give.
It's likely "You are an IBM employee 100% of the time" has a similarly complex backstory.
> I dunno, does your bakery need that cake? Are your tools at home equal or better than the ones in your office?
Ultimately, if the bakery explicitly says "stop putting your personal shit in the work display", you obey or be fired. Even if it's a better cake, or your at-home tools are better.
This is more like a baker baking things at home, and giving them away for free under their own shingle. That still lacks the nuance of software scalability and licensing but it's a little closer.