The obvious thing is that the arbitrary selected VID/PID may be already known to Windows/MacOS etc and the system load the wrong drivers. These drivers will not work with your PIC of course.

The second are Legal consequences I suppose, as you are using something that is protected and must be paid so you can use it.

I have not cared so far as I have limited production and cannot justify the expenses of 4-5K $USD. I prefer, as long as I can, to use serial or ethernet solutions but to read the long legal documents, you may apply and read them.

Ioannis