There is one advantage that BA has that no other airlines have: a "household" account. Up to four people can be a part of this account. I've got my girlfriend and two of her nephews in mine. Her nephews haven't flown with us but they allow us to pick up extra miles. Recently BA gave 250 miles to update accounts - thus an easy 500 miles.
[This message has been edited by doctorphil (edited 01-27-2002).]