Round corners happen by coincidence, and Apple wouldn't let you use round corners even if you met their spec.
Someone making a port the exact size and shape of a USB-C port (within tolerances) is doing it for the purpose of being compatible, and telling them to meet the (non-onerous) spec to be allowed would not get nasty headlines.
> Someone making a port the exact size and shape of a USB-C port (within tolerances) is doing it for the purpose of being compatible
People put TRS (3.5mm audio) jacks on random proprietary wall-chargers. They don't do it so that the charger can "be compatible with" the analog-audio ecosystem (what do you want to do; plug your charger into an amplifier?)
No, these manufacturers use TRS jacks, because TRS jacks (and sockets) are cheap parts. (Remember, they're not making these parts; they're just ordering them, in bulk, from some supplier that has a warehouse full of them. And that supplier doesn't care what they're used for; they just want to get them sold.)
USB-C connectors are now also seemingly beginning to be cheap parts.
I keep hearing about USB-C ports being significantly more expensive to use than previous versions, so I guess let me know when you see someone do that. I'll be surprised to see anything mass-produced that uses a USB-C port for something entirely different.
But even if they want to, it would be better if someone stops them.
Someone making a port the exact size and shape of a USB-C port (within tolerances) is doing it for the purpose of being compatible, and telling them to meet the (non-onerous) spec to be allowed would not get nasty headlines.