IMO/IME the size of the pad makes a huge difference too. A 4" yellow cutting pad would get my vote for most aggressive by PC, more so than the
Meg's 6" cutting pad; you can really *kill* clear with the PC using 4" pads even with sensible products (gee, ask how I know

).
Plenty of people have used the Meg's 7006 burgundy/red cutting pad via PC; they've even used it with Mike Phillips there advising (e.g., at an Autopia g-t-g a few years back). But one of those people cut through the clear on an older Benz with it too and that's a pretty serious mistep to say the least. IMO
Meguiar's doesn't want people using it via PC primarily out of liability concerns; note that they generally advocate mighty mild methods when dealing with people they consider less-than-expert. After an incident like the one I mentioned,
Meguiar's might've decided to nix the whold cutting pad/PC idea (at least as far as general public recommendations go).