The data looks valid. The account is set to “Per Activity” with none of the activities being public, so I can’t go to go into the details.
This doesn’t seem to really be a problem, especially compared to things much more visible like the issue of people accidentally not saving their tracked activity before driving home (leaving a long straight GPS track from the end of the activity to the point that they get home and save it) or people tracking intercontinental flights as ‘walks’. 
Those are real problems.
This confuses me - none of the paid features have anything to do with the lists of people throughout the site. So far, all paid features are very personal in nature - all geared towards helping the individual complete every street.
I find it interesting that you have other people’s achievements so wrapped into the worth of your own achievements. Your progress is great and should be celebrated without regard for anyone else’s progress.
This is also interestingly tied to First, second, third, etc. city completion badge in the same way that I disagree with that idea … Whoever is “first” to complete the city in CityStrides today is not necessarily the first person to complete the city next week/month/year. You can complete your city tomorrow, and someone can join the day after with data from 2010 that fully completes the city - you’re not “first” after that.
I understand and can appreciate chasing your city’s leaderboard, but the goal isn’t to have a higher number of completed streets than someone else, the goal is to complete all the streets. If we all complete all the streets in our town, we all end up in 1st.