If they're actually performing the vault with a landing, the answer would be "no" most of the time because at this point there should be no reason from a confidence perspective. However, I do sometimes cushion the table with a sting mat as a protective means...just to save the wear and tear on their wrists, elbows, and shoulders.
When kids are first learning to go over the table, I've always got them just doing handsprings to their back and stuff. So, "yes," I will often pull a mat over the table until they're confident and understand that the suede on the table is nothing more demanding than what they were doing with the 4 incher. It's just a little firmer.
The beauty of putting in this step is that is helps me to alleviate the need to spot, usually. Essentially, I'm just progressing on from the doing the handstand falls (to their back) that they've been doing in preparation. If I'm spotting, it's purely for shaping purposes and nothing more. If I have to spot for something more, then I've gone to fast with that gymnast and we need to back up.