I have noticed that the public bug submission forms of many open source projects adopt a similar approach.
That's where i got the idea ;-)
One thing, is that I don't think the advanced form should be restricted to uses above a certain level, instead just bury the option of which submit form should be used in the preferences under a slightly cryptic name,
Which would implicitly force any Anonymous Monk to use the "guided" form, without any (technical) limitations for registered monks. I like it!
BREW /very/strong/coffee HTTP/1.1
418 I'm a teapot