WP-Members has two options for limiting whether a post can be viewed by a user – restricted or hidden.
Restricted posts still exist in the WP query object when a user is logged out. They can appear in search results. However, when a user tries to access the content, they will be required to log in.
Hidden posts do not exist in the WP query object if a user is logged out. In other words, for a logged out user, any post marked as “hidden” simply does not exist. They are dropped completely if the user is logged out.