I'm a bit late, but I think a GBI provides MORE incentive for these kinds of jobs
At the moment, there's no way you could afford to live just from cleaning for 1 or 2 hours a day like many places require. But with a GBI, many more people would be available for occasional work like this, and the costs could be lower (no minimum wage).
In a GBI system, where's the incentive for anyone to do this?