Until a bitcoin exchange/business passes an audit by an outside/independent body (and continues to do so at regular intervals), why should
You don't need an audit. This is Bitcoin, you can publish a signed ledger and tree of debits showing your holdings in BTC, LTC, etc.
The fact that they are not doing so, despite being repeatedly asked, is very telling.
I pulled all my money out of btc-e, shortly after they refused to respond to the new protocols allowing the signed publishing of reserves and debts.
http://www.reddit.com/r/Bitcoin/comments/1yk4nv/please_ask_your_favorite_exchange_to_prove_that/