what i have been doing for over 5years is to use the same pass. i do not scratch out the date to validate the pass, but i turn the pass towards the driver and then use my sun shield to further shield the pass from view. trust me i have hiked well over 100x in angeles (mostly on weekdays) and have only been sited once. sent in the pass and had my father (a senior citizen who gets passes for $2.50) buy another one and i will will keep on going. honestly i understand why the forest pass charges $5.00 to play in our forests and it is not a solid policy. our forests are not helped by these fees but rather these fees allow for marginal help(trash cans,rest rooms,fresh paint, signs to congratulate what these fees do) sorry to rant.
but these fees must at least be equal to historically high levels of funding (i.e. 1800-1990) to qualify for these funds. we will never reach these levels again so most of the forest pass money(99.99) stays with washington. trust me this is only sinopsis of my knowledge on the subject. e mail me if you disagree