How do I stop cheating or unrealistic results?

Set a daily limit per user. Anything above it doesn’t count, whatever caused it.

Set the limit when you create the challenge, for example 30,000 steps a day. If the challenge is already running, support can add or change it from a date you choose.

There’s no automatic flag. To spot outliers, export the challenge and look for very high days in the Individuals (daily) sheet.

Very high numbers usually come from two devices or apps counting the same steps, or steps typed into the health app. See My steps are counted twice. Support can correct days from a screenshot of the source app showing the date and daily total, and can hide the person from the leaderboards while it’s checked.

Keep manual entry off, or limit how many days back people can add data. No system is fully cheat-proof.