In reply to mctrials23:
Standing there (legs slightly bent to absorb some of the energy ) with your hands ready to act (doesn't have to be above the head) is good spotting and can be effective, especially if you don't try to catch the climber but simply make sure they fall on their bum rather than their head.
Once the climber may fall twice his/her own height, however, it's pretty safe to say they're on a highball. That's not subjective. The bigger the weight of the climber (which increases with height due to acceleration) the stronger the spotter will have to be in order to modify the fall (bum first as opposed to head first), never mind stopping it.
Therefore, spotting a climber on a highball is useless after a certain height. Stepping away is probably the safest attitude, both for the spotter AND for the climber.
Moving the mats, on the other hand, can still be very effective.
And using as many mats as possible, even more.