The assumption isn't that they ran off with the btc. It's that someone else did, now they are insolvent, and to prevent the fallout they are trying to live off the float and hide their insolvency until they have made themselves whole again.

I personally would never give them my business ever. Many people won't either. I'm sorry, they already screwed me once last year holding withdrawal for 2 days, now again. They are going down in history. The only question, again, if they will return the coins. I doubt they will. Even if we assume incompetence, it doesn't mean they suddenly can't SPEAK, right? Go and tell your customers what's going on. When people are not open about things, it most likely means they want to screw you and you are safe to assume this to be the default version.

Even in the absence of overt theft on their part, if the real explanation is not what they are offering, then it is still very likely a scam. That is, they are not disclosing information to customers that would be relevant to the customer's decision to use their service.

So, for instance, with the fiat withdrawal problem, if the actual issue is that they are not solvent, but are hiding this fact in order to become so through trading fees (a popular theory), then they are shifting an extraordinary amount of risk on to the customer without his/her consent. That would represent willful misleading for their own gain.