I did not word my post appropiately. Surge arrestors are tested to a different standard then extension cords and larger wire sizes are required making them more appropriate than extension cords. Here are the restriction on extension cords from the IFC 2009.
605.5 Extension cords. Extension cords and flexible cords shall not be a substitute for permanent wiring. Extension cords and flexible cords shall not be affixed to structures, extended through walls, ceilings or floors, or under doors or floor coverings, nor shall such cords be subject to environmental damage or physical impact. Extension cords shall be used only with portable appliances.
605.5.1 Power supply. Extension cords shall be plugged directly into an approved receptacle, power tap or multiplug adapter and, except for approved multiplug extension cords, shall serve only one portable appliance.605.5.2 Ampacity. The ampacity of the extension cords shall not be less than the rated capacity of the portable appliance supplied by the cord. 605.5.3 Maintenance. Extension cords shall be maintained in good condition without splices, deterioration or damage
605.5.4 Grounding. Extension cords shall be grounded when serving grounded portable appliances.