I'm gonna repeat the question: why then is the buying pressure not 24/7 and only on China day time?
Where are you seeing that? At Bitfinex (Hong Kong)? At the Chinese echanges?
Apparently Mavrodi's ponzi (and Chinese copycats) are most popular in China. (Recall the MyCoin ponzi in HK, earlier this year? There seems to be a rich "market" for such things there.) Chinese victims are of course going to buy their bitcoins on Chinese exchanges, during Chinese day/evening time.
MMM doesn't need Bitcoin to steal money - Mavrodi has been playing this game for 25 years. He' currently active in China, India and South Africa at a minimum, but the website claims Thailand, Hong Kong, Philipines, Indonesia and East Africa as well. He's using bitcoin to transfer the money around the system - When the system cashes out we will see significant selling pressure.
Of course this is not the first MMM mega-ponzi, but this time seems to be different because he is using bitcoin to make victims all over the world, without himself being established in any country. This ponzi promises to be bigger, longer lived, and much more difficult to stop than the previous fiat-based ones.
Correct me if I am wrong, but I am assuming that the payouts too are in bitcoin (or in Mavros); and the victims are likely to keep or re-invest their payouts in the ponzi. So I don't expect to see a "cash-out" any time soon. There may be a big bitcoin sale after the ponzi collapses, if and when Mavrodi and his asssociates decide to cash out.
The question is how long will the Chinese authorities take to deal with these ponzis, and how hard will this impact bitcoin.
The most radical move would be to shut down all mainland Chinese exchanges and make bitcoin (wallet) possession a crime, then we could see single digits.
That is a possibilty, but only if the thing gets really big. In the nov/2013 rally, the Chinese traders imported perhaps a billion USD worth of bitcoins, which would have meant putting that much CNY in foreign hands -- all without government knowledge, licenses, custom taxes, etc. In retrospect, the dec/2013 decree was a natural reaction to that huge "contraband" activity.
Mavrodi's ponzi may bring back that scenario. However there are some differences: this time there are tons of bitcoins in the hands of Chinese citizens, so the cross-border flow of CNY may be smaller, since the Chinese victims will mostly buy their coins from Chinese holders. Or may even be positive for China, if foreigners buy coins from the Chinese.