I have both given and received.
As the receiver my spanker never told me to take my pants down she did it for me. She felt it was important that I suffer the embarrassment of being undressed as further punishment for what I had done and it worked. Believe me it really worked. I think towards the end, when neither of us needed each other, I would almost be in tears when she lowered my pants.
As the giver, it depends on the spankee. I had one spankee that was petrified to take her pants down, so I removed them for her. On the other hand I had a spankee who couldn't wait to get her clothes off to receive a spanking. She was very compliant in that and I appreciated the compliance.