To clarify your point: The price rose because some people had fiat waiting to be wired out, so they had to rebuy coins to move to other exchanges and sell there, right?
Well, that and I think many people panicked and took large losses. Now we do have a more steady buy at gox sell @ [the other three] maintaining the gap.
There has been such a disparity historically that people are trying to get passive income from OkPay helping others with arbitrage.
https://bitcointalksearch.org/topic/mtgox-btc-e-arbitrage-3-profit-171349 It hasn't been just a couple of days.
I don't really have a good reason for the stagnation other than artificial shoring of the price. Now why or who might have done this - I don't know but some unusual stuff is happening at Gox. Hell, for all I know Gox is manipulating the market because they are a key member of The Bitcoin Foundation and they needed to stop U.S. trading because of the California complaint against TBF. They did just file for a FinCEN MSB license. Maybe that's got something to do with it. But that's just a wild assed guess.
Yes, there has been, and it took an event that would cause selling on MtGox to temporarily become unfavorable. Not 20% though - we've never seen it that large before. The initial panic on this no withdrawal news brought bitstamp down to 90 while gox was still holding steady near 110.
Also, I think Gox is definitely up to something. The whale wars on the 24th simply make no sense. Something happened there that us outsiders dont know. Rich people dont just throw their money out like that.