the problem are not bots the problem is the verification. It could be done this way:

The same way we elect witnesses we elect sentries that take care of the verification. These sentries can then vote in or out participants from the universal income list. The verification itself could be done through video chat and / or local meetups. For example to be verified one must get verification from two verificators that are drawn independently. Optional we could also require a security deposit for each new participant. In case of cheating 50% of the security deposit is destroyed, 50% is given to the one who found the double account. This would economically solve the problem of double accounts.