Strava already has an option to mask your starting location. It tracks it from your house, but the public data hides a certain radius around your start and finish locations
I already use this feature but I can reliably find my driveway on the heatmap so either a) they aggregate everything into the heatmap regardless of the privacy sphere or b) it's from my friends visiting, picking me up, etc.
Either way, there's a very clear route that leaves the road at my house and follows my driveway. It doesn't take much effort to find many, many more examples of this throughout the heatmap.
The problem is that it’s not available in the mobile apps and fairly well hidden on the website. For a big public data dump it seems like a reasonable precaution to assume many users aren’t aware of that feature.
Either way, there's a very clear route that leaves the road at my house and follows my driveway. It doesn't take much effort to find many, many more examples of this throughout the heatmap.