In this particular case it was just a proof-of-concept, albeit at scale. We did not run a proper ground-truthing process but people actually running that type of data model in production could have ground-truthed the analytic model if they wanted to.

However, it turns out that thousands of people like to talk about their flights on social media, so we scraped that as a spot check and it mostly lined up perfectly. Good enough for a demo and it would have been difficult to come up with an alternative explanation for the patterns in the data.

The purpose of the PoC was to sell the data analysis infrastructure that made that type analysis possible at scale, it wasn't about the data per se. It was a compelling demo we invented given the data that happened to be available. Startup life.

i don't have any special knowledge in this area, but just thinking about it idly while sitting here, "robbing their homes while they are away" comes to mind as a good proxy.