Ideally, gymnasts should not need a spotter in competition. Not for warm-ups. Not in the meet itself.
If I see a gymnast being spotted, I question whether they are physically, technically and / or (especially) psychologically ready.
There are exceptions. Spotting or sliding a mat for release moves on Bars can be good coaching.
That photo was linked by Gymnastics Zone — The Perils of Coaches Standing There Instead of Spotting
When is it appropriate to stand-in for a gymnast?
If something goes wrong, are you ready to spot?
Gymnastics Coaching.com 