Yes. Tier ‘downgrades’ happen when you don’t earn enough points during Reward Period 1 or 2.
Refer to the chart. Let’s say, if you don’t earn enough points during Reward Period 1 (1 Jan – 30 June) to maintain your current tier, you will lose your tier and the privileges that come with it.
For example, your current tier is Platinum. You will stay on Platinum from 1 Jan- 30 June (Reward Period 1). However, if you take 0 rides during that Reward Period, your Platinum tier would be ‘downgraded’ to the basic ‘Member’ tier.