Well they can definitely challenge the courts jurisdiction on the matter, and it would be up to CoinLab to prove that Mt. Gox was doing buisness in Seattle (Washington Western District). It sounds like Mt. Gox doesn't want to sell off its US customer base, at least not yet.
It is very unlikely they can challenge it successfully. The contract contains a choice-of-forum provision specifying King County Washington and agrees to personal jurisdiction.
It's at least somewhat likely Gox can win there or anywhere, though. We'll need to know more details before that can be judged, though.
Specifically:
Quote
7. The Agreement provides that the Defendants “irrevocably consent to the personal jurisdiction of and venue in the state and federal courts located in King County, Washington with respect to any action, claim or proceeding arising out of or relating to this Agreement.”
8. The Agreement provides that it shall be governed, construed and interpreted inaccordance with the laws of the State of Washington.
8. The Agreement provides that it shall be governed, construed and interpreted inaccordance with the laws of the State of Washington.
Such choice-of-forum and choice-of-law provisions are routinely enforced.
