This movement doesn't mean much because the amount of coins withdrawn and the number of people that are participating in it is minuscule and is by no means a good way to prove the solvency of an exchange.
It doesn help either if the date the withdrawal will happen is already known and the exchange can act to buffer its effects. Why panic withdrawals due to price drop or increase affects exchanges some of the times is cause they were unprecedented and the exchange will need to take some time to process transactions by first suspending withdrawals for a period of time.
Actual proof of reserves should be done by independent bodies with full transparency of the results and also access given to users to check the status of cold wallets