The Optimum instructions recommend a dampened pad for hand application, but not for machine application.
Excerpts from those instructions:
Hand Application Apply to a small area with a dampened foam or cloth applicator.
Machine Application Apply with orbital or rotary polisher and appropriate pad for the job. Apply just enough product to create a lubricating barrier between the buffing pad and the surface. Work across the area until product disappears.

Since I use PS with a PC, I don`t dampen the pad, but would there be any benefit from using a dampened pad when using the Poli-Seal with the PC.