"Store Door Camping" is the cultural spawn of Father Consumerism and Mother Hype. It happens for retail sales, garage sales, games, or basicaly anything bought or sold with a announced sale date. Its kinda like a county fair, with far less flashing lights usually.
It is a social event.
Since I don't buy into hype and my budget doesn't allow for attending the event in question, I don't Store Door Camp. I look for a discount on the Steam store price after word of mouth or a trusted review after the game has been released.