Would be good to have some way to add users directly from the Relationships tab of the user settings page https://www.inaturalist.org/users/edit#relationships
Right now the only ways to trust a user with hidden coordinates but not follow them are to:
- follow the user, go to the user settings, Relationships tab, and then uncheck the box next to follow and check the box next to trust with hidden coordinates, or
- find an observation of yours where they have added an ID/comment, click the arrow in the top right corner of their ID and select “trust this person with your hidden coordinates” (thanks @vynbos)