I am not a bund trader but in the past I always heard the flipping was the problem. How about the flippers ? They are not a problem anymore ? Also i must add that all the machines will become a real problem for big hedge funds when they are not there anymore. Lets suppose the bund crashes 2 full points and stays super volatile. All machines will back off for a while and no human market makers are left anymore. The market will become super illiquid and billion dollar hedge funds that are used to reverse their huge positions with little slippage will not be able to trade anymore. This actually applies to all markets. So I think the machines make the market more liquid and less volatile at the moment. But when a crash scenario appear they will cause the opposite. Good luck trading - and always save enough money so that you have some cushion - because you will stop your trading carreer at the worst point for sure !