"They" don't, george.  The limit applies to everyone, and was made necessary by the fact that some O/G firms decided to hit the courthouses en masse with armies of abstractors who monopolized the computers to the point where no one else could get anything done.  One courthouse in my area even put a limit on the number of examiners that any single company may have in the Deed Room at any given time.

It's called being considerate of others.

Regards,
Scott Perry