Well to be fair to traders, you can't really trade from a remote wallet. The coins have to be in an exchange wallet and ready to buy/sell frequently. The price swings so fast, and sending BTC from a remote wallet to an exchange wallet can take anywhere from 5-10 mins to in some cases an hour. By the time you are ready to sell them you may have missed the opportunity.
I can't feel too sorry for traders... the REASON these short term opportunities exist is because careful people keep their coins offline. If you didn't factor this risk into your calculations you made a bad trading mistake.
I feel sorry for newbies who read a few online articles, bought a few coins on Gox and just left them there (for a variety of reasons, time being one)