I also never said business would stop, if some funds are frozen. However, accounts are stopped. It is not a large step to see how this could happen to Gox in JP, In fact I am sure coin labs lawyers are watching with interest.
Note that it wasn't MtGox's accounts which were frozen. The accounts belong to Mutum Sigillum LLC, their payment provider. There has been no word from them about their involvement. Probably got a national security letter with a gag order. This is "Land of the Free" after all, not Soviet Russia.
It is unlikely that MtGox had much money there. From IRC a while ago:
< DeLorean7> How long have withdrawals to Dwolla been taking?
< DeLorean7> It's been a week... I'm getting pretty worried
<@MagicalTux> too long
<@MagicalTux> right now we're around 2 weeks delay
<@MagicalTux> we're not putting funds in Dwolla to avoid funds being in limbo