I once put an Amiga sticker on one of the prototypes (some years ago) and got shot down by CUSA on the forums and via "scary" emails... 
so never again.
I let the user decorate it. 
I don't think they could have won in court case. The court probably would have ruled on your side. I don't know who gave them permission to use Amiga trademark. But whatever floats the boat.
