[mtmail]

> I suspect they want to review and check every inch of OSM in an area before they import it.

Facebook does the same with OpenStreetMap data. With a combination of automated tools and team of manual reviewers they were months behind with updates to allow error detection.

"Some of these contributions may have intentional and unintentional edits that are incompatible with our use cases. Our mapping teams work to scrub these contributions for consistency and quality. In the course of this work, we also build additional tools and technologies on top of OSM to increase mapping speed, and more importantly, drive a higher level of detail, quality and accuracy on the map." https://daylightmap.org/