I watch Huobi, which is one of the Chinese exchanges that is a leader in no-fee trading. I find the volume numbers on Huobi plausible. I am not a trader now, but I believe no-fee trading greatly facilitates the high volume.
Watch the CoinSummit youtube video with Bobby Lee and especially the telltale signs he mentions to see how Huobi in particular is suspect (possibly worse than mtGox), zero-fees are actually needed for this kind of fraud, otherwise your own investors might get wind of it (because you aren't making the profits your website says you are if you sell to yourself).