TL;DR (if I understood correctly): don't use prefixes, use non-deterministic ways to raise the entry barrier. Like: 1. Developer registration & usage keys. 2.

TL;DR (if I understood correctly): don't use prefixes, use non-deterministic ways to raise the entry barrier. Like: 1. Developer registration & usage keys. 2. Global usage caps. 3. Feature auto-self-destruct. To me it seems just a way to use early adopters as A/B testers, and yet make it impossible to them to rely on a experimental feature. I doubt this can work at a scale without extreme sufferance or effectively wiping out the usefulness of experimental features.