I don't think it happens in regular intervals as I have seen it happen twice in 1 day.
but now that you mention it, they do happen around the same time every day.
just looking at the orderbook there's not even anything for sale more than like 1.5 btc worth but every day like a 50 BTC buy at the lowest price.
Why do u doubt that? if there is one thing I know about Yorbit its that I wouldn't put anything like that or any other scam past them.
The whole IOU thing seems scammy and if their willing to do that do I think they would sell to themselves to create volume and interest to scam people out of a few more bucks .. hell yeah.
cisahasa sig is right on the money.