HN user
Don't join clubs with people you cant't trust. Post your rides with week delay or make them public when you are back home from your trip. It is called "enhanced" privacy mode for a reason and combined with other privacy settings it can give you very good results.
They posted their data as public so they could be found and identified anyway. Heatmap just speeds up the process by letting us know where to search.
You can also opt-out of segment leaderboards. With some work you can lock out your account so only your friends can see your routes, photos and stuff. Everything is well explained on Strava support webpage in section called "Privacy Settings".