On a membership site, search can be an accidental leak: it lists titles and descriptions of content the visitor has not paid for. Member-aware results stop that.
Turn it on:
In PRO Settings, under Search Power, tick Member-aware results.
What it does:
Before results are shown, each one is checked against the current visitor. Password protected content is hidden, and anything not publicly published is only shown to a user who is allowed to read it. A logged out visitor and a logged in member can search the same words and get different, correct results.
Working with a membership plugin:
Membership plugins can hook into the rasp_user_can_view filter to apply their own level rules, so a developer can wire your specific membership system into search visibility in a few lines.
A note on performance:
Each result is checked individually, so this does a little more work per search. It is well worth it on a paid membership site.