How do the big boys cover there arses

[viper.trader]

So lets say someone with a large pot backed £10.000 to then lay, let's say 10 mins before a race starts, then betfair goes down before the lay load goes in, you could turn to betdaq but that could not handle the amount needed before the off, so what do they do, what if it was £50.000. Also say someone with a hugh pot wanted to bully say a football market a couple of hours before kick off how much money would have to be dropped to create some serious movement, lets say 10 ticks. How much does the bomber drop to take something from 6 to 100 then back up again.