Bob is correct, I do the same thing to get my backpacking permits. I've been able to get on heavily impacted trails on holiday weekends that way. The only time I had difficulties was at the Mammoth office when I wasn't first in line. The Ranger spent a long long time planning someone's trip for them while a long line of frustrated hikers went out the door. Meanwhile, the permits got snatched up from other Inyo offices moving much faster. That could happen anywhere, so be early if you try this approach.
