Mike,
It is really not a matter of do or don't do it cold/warmed up in place-- i.e. no "black vs white". More shades of gray.
Yes it is BETTER to have the oil up to operating temperature, but the world will not end of it is changed cold. And, yes this happens at dealers, but that does NOT make it the best way.
Personally I change engine, transmission oil bath front axle and rear axle only after driving, but if I could only change it now where it sits or run it way too long on old oil, particularly with HEUI pump, I would also change it now.