Jeans are allowed to be worn in lieu of the uniform trousers as an economic necessity-- not every kid who joins a troop comes from a family who can afford to buy everything a tenderfoot scout needs to have. For some folks $35 for a pair of "wear to meetings" pants is a stretch too far. One of the purposes of Scouting is to give every scout the opportunity to take part on a equal footing with every other scout. Allowing jeans to be substituted for regulation pants provides just such an opportunity for scouts to take part on a equal footing.

Anyhow, this is really getting off, waay off, topic.