OP here. Audited GreenCloudVPS's "100% renewable" badge. REC purchases: 12 GWh/year. Actual footprint by prefix geolocation: 8.3 GWh in AS20473 (NJ, coal-heavy grid), 4.1 GWh in AS63949 (TX, gas-heavy), 1.2 GWh in AS14061 (AMS, actual wind).
[NJ] ===(REC)===> [Wind farm, OK]
[TX] ===(REC)===> [Solar, CA]
[AMS] ===(PPA)===> [Local wind]
RECs don't follow electrons. Their NJ load feeds from PSE&G. The OK wind farm? Not on that grid. This is basic physics. Anyone without ASN talking about "green hosting" is buying marketing.
RFC 8468 (IPPM) applies: you measure where the bits land, not where you wish they landed.