Originally Posted by floridatennisdude
You'd still have spots that don't get a good angle to look at. In volleyball, they stand right on the corner with a perfect line of sight down a baseline and sideline. Due to the net in tennis and the service line, you need 5 per court to have someone at the fence calling a line.
First of all, the major issue of course is the cost.
Secondly, as JLyon pointed out, the chair umpire has a pretty good look at all lines except far sideline and center service line. You would definitely not need a chair + 5 line umpires at a college match where the players are calling their own lines and the umpire is overruling a clear mistake only upon verbal appeal from the players. There are professional events and high level ITF juniors events where the chair umpire is calling every line on the court without line umpires at all.
One conference, I think it's the Big 12, has a chair umpire for every court, and during the doubles, the three that are off go and stand on the far sideline. I am not 100% sure of their protocol, but I believe the player still has to appeal to the chair umpire, who then has to decide whether it was close enough to yield to the official on the far sideline.
As a chair umpire myself, I know that there are certain umpires that have no training as a line umpire, and no business standing on a line. It has the potential to cause even more trouble. I would rather have a couple of very close balls that the players might make an occasional error, than having a few close calls where the players are right, and the person standing on that line makes an error by overruling it.
I don't like the system of line umpires in college tennis at all.