Joe,
Let none of those builders come to my town and try to buy their way out of code compliance. 210-52 is there in large part to avoid the use of extension cords.
The majority of residential fire investigations I've been a part of in one fashion or other have been electrical in origin. Many, many of those were as a direct use and miss use of extension cords. Yes there is a safety issue, otherwise the requirement would not be codified.
Overheating due to load or crimping under the chair or sofa leg is a common origin of fire involving extension cords.
