Uber's official tipping policy changed last year to suggest that drivers can ask for tips, have tip jars, and HBR suggests trade tips for reviews. https://hbr.

Uber's official tipping policy changed last year to suggest that drivers can ask for tips, have tip jars, and HBR suggests trade tips for reviews. https://hbr.org/2016/05/ubers-new-tipping-policy-is-a-mistake https://hbr.org/2016/05/ubers-new-tipping-policy-is-a-mistak... An uber driver even offered square for tip.