As a resident of Southern California, I'd say the PGA of America would have a lot more success with their "Tee It Forward" Campaign if they'd print the "Tee It Forward" signs in Korean or Japanese.
Don't take me the wrong way, but at the public courses in the South LA County area, the greatest culprits are most likely either Asian, or are duffers who don't play enough golf to know better. From my experience, the semi-regular customers play the tees that best represent the tees they will play in their club tournaments, or in their money games with their peers. As long as they keep moving, I have no problem with a short hitting 20 handicapper playing the back tees as long as they're ready to play when it's their turn. The way I see it, if they want to get their butts kicked, it's their money. But if they're slowing the course down by meandering around, not playing ready golf, and not keeping up with the group in front of them, that's a different story.
I frequently (I probably average about 1 rd per week) see older guys/gals groups play the back teees and keep it moving enough that it's hard to keep up with them. They know their distances, they are ready to hit when it's their turn, and they have long since dispensed with the Ben Crane/Kevin Na pre-shot routines. On the other hand, it's disconcerting to watch a player hit his tee shot 180 yds on a 400 yard hole, then WAIT for the green to clear before hitting his second.
Be ready to play when it's your turn, know the rules, and keep up!