Actually, mayonaise doesn't require refrigeration at all:
Mayonnaise Spoilage Myths

However, we are used to keeping it in the fridge, and warm mayonnaise does look different than cold, and we're all mor eor less collectively trained to believe that mayo that is more gold is spoiled. As a culture we seem to prefer cold mayo, or be afraid of warm mayo, hence the reason it is often served chilled, even though there is no real need for it.

MNS