I've always had a question and concern: on major exchanges, stock contracts often have very low liquidity. If market makers notice there's too much 'easy prey' on one side and then deviate from the normal stock price to spike and harvest them, is this considered normal market behavior? (After all, there are disclaimers, no one-to-one correspondence mentioned, and no clear definition of how much deviation is normal or abnormal.) Or would they act to protect their reputation and require the relevant parties to return the 'improper gains'?