As a buyer I'd be just as unhappy to be unable to get the hardware. I already have some, but if I wanted some new feature it doesn't have and that open-source definitely doesn't have, I'd be miffed to say the least if I couldn't get it just because Bambu didn't release the source code.
I see how it could be inconvenient for you, but should it being inconvenient for people be a valid reason for letting them continue to break licensing terms when they could end the whole situation immediately by stopping breaking the licensing terms?
Any import block would be on the hardware, not the software. And the software would need to be released for other territories anyway.