I'm not sure what either of you are saying about warm ups. but for me, I don't do them. I just get on the bike and ride. The only thing going really hard in the first five minutes of a ride has done is to keep me from going hard during the second five minutes.
I do find now that I have a PM that I can put out more power for longer intervals IE, 60 second power, after I've been riding for over 90 minutes than I can after only 20 minutes on the bike. And even before getting a PM I was finding that some of my PR's were also after riding for quite a while.
So if warm up is 60 to 90 minutes of riding, then I guess I am doing a warm up.