For example, there is finance audit request by community. I pack data into zip archive with password and password is released only after 1-4 weeks. Otherwise, imagine situation:
There is one big account short on bitcoin - let's say 40K BTC. Everybody see it and trying to do short squeeze - pushing price higher to force liquidation.
LOL, I agree. It would suck to make that public info right away. A public "Short Interest" report once every 1-4 weeks without individual account identity is more than enough.
Edit: Btw, community requested audits are more about the exchange itself and general operations rather than about their customers.
Edit2: BTC-e's BitInstant Reserve balance clearly displayed on their website (https://btc-e.com/) is a good example of some transparency which doesn't reveal customer info.