I tend to think it is a more serious problem that only certain insiders are fully informed about. Not to sling mud, but I would cease all dealings with Mt. Gox until the issue is made public. Personally, I stopped dealing with them around the time of the CoinLab partnership announcement. Whatever happened to that anyway...?
Finally, mtgox prices are higher for all currencies. Just checked bitcoincharts. Not a USD specific issue - it's a mtgox issue. Not convinced the $2.9mm US Gov seizure is the end of the story, or itself enough to explain this spread.