Logically, if you bot for more time, you are giving them more data to analyze and repetition sets in if you are only doing 1 task. Also, if you are at a hotspot for a longer period of time that increases the chance of you getting reported and/or bot-busted. But I know what you mean- I don't think they really take a look at total daily play-time as a factor in determining whether or not a player has used a bot. It's the consequences of botting for long periods of time that matter, not the fact of how long you are botting.