Since this seems like an obviously attractive alternative, I assume it's somehow not feasible. E.g., BM has fences and guards to prevent our going out that way, or ...? (I'm not sure why they would have this rule, but it's the only problem I can think of.
Similarly, I remember when I finally got onto the highway, which was proceeding pretty slowly, there were trucks proceeding rapidly along the playa to Gerlach. This would be another attractive alternative to the long exit waits, so I'm guessing this must be strictly prohibited also.
So, anybody else tried that? Did it work? Problems? If taking an alternate exit violates some major rule, please tell me about it calmly.