One can argue, as Bryan does, that populism is more dangerous because the people are really, really ignorant. [Actually, I argue that the people are really, really irrational! -B.C.] However, my counter-argument would be that non-libertarian elites may be more dangerous, because their additional incremental knowledge is exceeded by their incremental arrogance.
The key thing, though, is that most non-libertarian elites are still markedly more libertarian than the general public. Once you keep that in mind, why does arrogance per se worry you? Arrogance might lead elites to go full speed ahead with popular statist measures, on the grounds that "We know how to get things done." But it could also lead elites to turn a deaf ear to popular statist measures, on the grounds that "The people don't know what's good for them." When you look at all the popular statist policies that don't happen - or happen only in a watered-down form - it's hard not to give some credit to elite "arrogance."
Just off the top of my head, a good example would be wage-price controls, which the elite were enamored of in the 1960's and finally got to experiment with in the 1970's. Bryan may be a bit young to have as vivid a memory as I do of how that played out.
I bet that Arnold's right that the elite favored wage-price controls. But I also bet that the elite favored them less than the public. At least among the elite, there's some sense that controls cause shortages. For the public, controls and shortages are practically unrelated.
A year ago, I bet that an referendum would have imposed price controls on gasoline. It's thanks to "arrogant elites" that we avoided a re-run of the '70's.