Discounts don't motivate people - other people do. But you knew this already.

Motivating behavior is challenging but not impossible. Change agents, including mediators, have to “prime the pump.” Want people to tip your services? Put money in the tip jar. Want people to laugh at your jokes or cheer your band? Plant a “stooge” in the audience. The rock band KISS did this to great effect and it led to a record deal. Want hotel guests to reuse their bath towels, saving water and labor costs? Plant a sign in bathrooms that indicates the majority of guests reuse towels more than once.

Same with re-usable coffee cups. Many people who feel awkward about carrying around a reusable cup grow more confident when they see others do the same thing. Moreover, we feel loss more intensely than gain - in other words people hate paying extra money for a disposable cup to a greater degree than the pleasure of receiving a discount for their reusable cup.

This dynamic reflects the reality of unconscious “loss aversion.” We will fight harder and assume more risk and expense to avoid a perceived loss. Once we perceive a gain, however, we become conservative, avoiding risk and expense. Thus, agents of change, including mediators, are looking for ways to readjust the point of reference where a loss becomes a gain.