Going further, it would be trivial to randomize delays and user input, but the more difficult thing would be to make it random in a human way. Human input is obviously not random but fits into detectable patterns with certain levels of variance. I'm sure the people running the sites could use all sorts of stats in their bot detection algorithm such as when the time gets past midnight in the local time zone human users starts to get sleepy and the avg response time goes down by 50ms or whatever...