Apparently even climbing companies have been denied access and sent off at the gate, despite having a letter from Shivapuri National Park.
With a couple of other climbers, we were thinking of writing a letter to the head of Tourism Year 2011 and the ministry of forests and National Parks, signed by different trekking companies, saying that this is not acceptable practice.
Trekking companies are losing, and they're losing revenues for the park as well.
There seemed to be a problem, with too many people coming, perhaps degrading the site. But then they could easily post someone there to make sure people respect the site and understand what a "conservation area" is; that would be much more useful. This is not justified in terms of security either, since one need not be experienced to get a permit. This is just useless bureaucratic hassle.
Biking sounds like a good solution. And if you are caught, just say you didn't imagine such stupid rules could even exist.