Hi,
the idea was same. If there is a marked route in OSM (at path A) and Strava says that the nearby path (path B) is used a lot more (actually path A is not used according to strava). This leads to a conclusion, that path B is marked and not path A.
Also it was reported by user, which walked this part of marked route, so I have no doubt about it (reported by user, verified on Strava).
Now I can answer your question: I was not modified based only on Strava but primarly on user report.
Best regards.
V