Effect of hiding the exchange, it's the wrong liqudity Gromit?

the exchange is more or less just traders and wannabe traders competing with each other anyway.

i seriously doubt bookmakers use betfair much at all, they dont take big enough bets to need to trade out of them. i take bigger bets every day than any of the major bookies would take. they only want the £5 bets off idiots these days.

You're making assumption that they'd balance off every bet as they come on here which would be a bit mad. I'd see them take their piles of bets periodically, analysing their total position, then pitching some money into here as a lump if they don't like what they see and to make their own position nicer. I was on understanding that was done.

I find it hard to believe the big lumps that come flying in are all done by traders. Or bright ones anyway.

lol no i know they wouldnt lay off individual bets.

i just doubt theyd bother laying off anything. it would make an absolute mess of all their accounts for a start. small independants may lay off if theyve got a potentially damaging accumulator going or heavily one sided book. i doubt larger bookmakers bother.