Point of sharing is to do it after main players staked. That way you have plenty of people betting it and bookmaker cant void it easily or lock your money..So yes, big stuff often remain behind closed dour if available in Asia but for these bookmakers it is better to spread
There is no such thing as a fixed game. Those who have info about fixed games surely won't give it to others. The more people bet on some event, odds drop. Nobody is that stupid.