Filters whether or not a member has signed up for a trial in the past. Restrict Content Pro only allows users to sign up for one trial by default, so you may want to use this filter if you want to allow a user to sign up for multiple trials.
- $has_trialed (bool) - True if the member has used a trial, false if they have not.
- $user_id (int) - ID of the user being checked.
This would always return "false", which would allow a user to sign up for multiple trials:
add_filter( 'rcp_member_has_trialed', '__return_false' );