I suspect people are more concerned about getting their money out at all, than just waiting a month. Why else would you pay a 20% premium?
If you were buying coins now, you wouldn't be wiring funds to Gox and paying a 20% premium. The only people who would pay that are those who (unfortunately) have fiat funds there waiting already.
Also, Gox would be for traders. Try trading on Stamp, it is hard. You could keep your coins on Stamp and trade with some on Gox as there is the action.
I trade regularly on Stamp, without any major issues. TBH, it tends to be a bit less erratic, IMO.
I take your point though that traders are looking at relative prices, rather than absolute prices. I'd still be a bit concerned about Gox's future, considering the way the market is pricing the risk already.
Yeah, the price movement is on Gox (and originates there). Look at this last movement. Nothing happened on Stamp for a while, then suddenly a $4 movement and then it backed off.
I am also really worried about Gox. It might end up being nothing, but how long ago did that 2 week freeze on wiring money end? About 2 months ago or so? And it was only supposed to take a few weeks to get back to speed (backlog as Gox said). Now - NO WORD, zero...