And that lawsuit would be with what reason?
As far as I know, all backed GPD Wins have been shipped. They are also replacing broken devices (a bit chaotic, slow with replying emails as far as I read here, but they're doing it).
Letting the customer pay for shipping costs back is legal internationally.
So yes, while they could provide a better customer support (either paying shipping costs or by using resellers like me to collect all broken devices of an area and shipping them all together to save shipping costs), but I don't see anything that you could sue against.