What do you mean, "selling without being able to rebuy?"  What stops you from re-buying?

These flash crashes keep happening, one or more every week.  If you sold, then you have cash, so you can place limit buy orders.  If you keep a limit order at 10% below the all time high, you automatically get bought back in at the next flash crash.  What stops you from doing that?

Or are you trying to time the bottom, and then keep getting locked out by the Mt.Gox lags?  The solution is to forget about trying to catch the falling knife.  Instead, be content to automatically buy at 10% below the all time high, ride it back to a new peak, then repeat.

Sure, you could theoretically make more if you could time the bottom right, and not get locked out of trading my the Mt.Gox lags.  But neither of those is possible.

This strategy maximizes your long-term profit by helping to stabilize the market.