While I was waiting for my withdrawal that took 40 hours i did some math.
Somebody had a very good week and won 79 BTC = $20.000
It was very suspicious that there is lot liability on the markets.
Basketball (at 2015-10-13 20:40 CET ) : 1180 market : back side: 4589.986; BTC lay side: 4896.957 BTC
Only basketball : lay + back : 9487 BTC !!!If you place bets on both side (lay, back) on the same market that is unmatched then fairly subtract both amount (back amount and lay liability) from your account.
At betfair if you place $10 on back side and $10 on lay side (liability) then your account balance will decrease only $10. (Initial account balance 271.06, after unmatched bets : 261.06)
At fairlay if you place 10 mbtc on back side and 10 mbtc on lay side (liability) then your account balance will decrease 10+10=20 mbtc. (Initial account balance 27.36, after unmatched bets : 7.36)
So we have to add lay + back side at fairlay to get how much BTC is in the system.
Soccer market is much larger which means that somebody who makes the liability
had to deposit at least 35.000 BTC to cover/offer all market .
So you play against fairlay and not other bettors. (Fairlay did not tell this to you.)
So if somebody won 79 BTC in one week and you have to wait 40 hours for your withdrawal then you start thinking.
Lay to back conversion is inaccurate. and so the converted amout that is available.
For example: 1.15 lay odds = 7.67 back odds (and not 7.71)
if you click on 1.149 you get 7.71 and not the accurate 7.67
lay = 1 + 1 / (back - 1);
However , the conversation sometimes is accurate (near 2 or not game market? )
Liability explained
Your liability is the amount you could lose in your worst-case scenario.
When backing it's simply the stake which you place. When laying however it's the amount it will cost you if your selection wins. Either way, it is how much you are risking.
I run into another bug while testing the lay back system. I placed back and lay side on the same market that (unfortunately) matched (i gave wrong lay price ) and now there is only 1 matched bet in my history. My initial account balance was 0.1 BTC and now it is only 0.027 BTC. I did not get back the cancelled 0.0435 BTC.
So I went back to pinnacle. Fairlay is very risky.