The Verge has a great post up about same-day delivery:
Postmates and WunWun each took almost exactly an hour to get to me, though my 18-year-old WunWun messenger told me it was mostly because the Starbucks line is really long. In each case, they handed me a phone with an app running, asked me to input a tip and sign my name, and were on their merry way.
For delivery of miscellaneous items, does it really make sense to tip as a percentage of the total delivery value? What if you order something that’s very small, but also very expensive? If this sort of thing catches on, I wonder if it will become common to tip as percentage of the total weight, rather than total price. That’s the only way it really makes sense to me.
Well, that, or business owners could just pay delivery people, waiters, etc. a decent wage and stop expecting customers to pay a majority of their employees’ salary.