Unfortunately cheating on Strava segments seems to be fairly common. Suggestion for cycling activties is to require a heart rate monitor and power meter to an obtain a leaderboard ranking. For running, etc., require a heart rate monitor. At a minimum, a heart rate monitor for activites would be a step in the right direction. This would help maintain the integrity of Strava. Will it solve the problem, no. But the change would definitely help expose cheaters.