Interesting, if they switch to a corporate account then many laws protecting "consumer" accounts don't apply. Also with a corporate account with most banks they can do alot more with the funds, for good and bad.
They don't "switch" to corporate accounts. They never really had proper segregated accounts in the first place.
There is exactly one bitcoin exchange that has segregated user accounts (to be perfectly fair it does not appear to be necessary in the US where an MSB license, or a partnership with a registered MSB is sufficient).