includes/warning-repair.rst:

Warning: In general, if you have an intact copy of your data, such as would exist on a very recent backup or an intact member of a replica set, do not use repairDatabase or related options like db.repairDatabase() in the mongo shell or mongod --repair. Restore from an intact copy of your data.

This warning needs to be revised to make clear it's written in the context of suspected corruption.

Users who visit the db.repairDatabase() helper page in the context of wanting to reclaim disk space or rebalance their indexes will be confused by it.