Well until I saw a comment below reitterating that the bots interact with blockchain and not the UX so this may not be possible.

Quote from tarazkp:

this idea got shot down as the bots do not need it anyway. They interact directly with the chain, not through the interface. From what I have heard, there is no way to identify a bot from human. I keep pushing this point though.

The only other solution I can think of is randomly changing the voting period for max reward per day using voting information from the previous day.