Although I completely agree with using a least agressive approach, I don't believe the yellow pad and polish were completely responsible for the incident. You did what is commonly recommended; start with the least agressive pad and polish and increase agressiveness as necessary. I do believe paint can be damaged via the PC or any other polisher if common sense is not utilized, however, I don't believe this is the case. I remeber reading a post from Totoland Match were he indicated he was never able to detect a significant difference in the thickness of clear coat after compounding with a DA. In fact, a significant difference was only noted after compounding three times with a rotary. I suspect the clearcoat was already damaged; maybe consequent of being covered by the decal (adhesive, etc). I don't feel you should fear using agressive techniques if it is necessary. Of course, all of this is simply a matter of personal opinion. Hope this helps.