It is not possible to predict when exactly pump will happen. It is true that we can know exchange address, monitor it everyday.
But how we would know if the coins transferred belong to whale who is preparing for giant dump or it is internal exchange transfer?
We have no idea how much time someone decide to keep coins in exchange's wallet to dump it someday.
I can accept a case where monitoring is not possible, as explained above. But if a transaction IS visible, then it's a different story, regardless of its nature;
1. How many large size transactions are there? And by "large size" I mean the size that has a the potential of a significant market affect (and effect). >$5M ? or >$10M worth of coins?
2. Of those transactions, what percentage (an assumption based on historical data) were a dump and what were a legitimate transaction?
3. In both cases of a dump and a legitimate transaction - it's safe to assume that a cash-out will be involved, due to the amount at hand.
I think, even if just 20% of dumps (or huge transactions) can be spotted, it can be super-beneficial.
And even if it'll turn out to be a false-positive, you can buy your coins back at a similar price you sold them, a day or two later.
But, it's just a noob thought...