Moodle docs gives the impression that the higher an enrollment method appears on the list of supported methods for that course it will take precedence over other enrollment types.
"To change the order in which the enrollment methods are checked, use the up/down arrows. If a user can enroll via more than one enrollment method, the one highest in the list wins."
This is not actually the case.
Create two courses.
In both courses manually enroll a test student.
In one of these courses, add the course metalink enrollment type and link the other course.
In the first course you will have a user that has both Manual and Meta enrollment types.
Ensure that the manual enrollment type is the highest on the list.
Set the manual enrollment to suspend.
Log in as the user and access the first course.
EXPECTED - You should not be allowed as the manual enrollment should override the metalink type.
ACTUAL - you will be allowed to access the course.