The field in the database is called "autoaccept". It controls the initial value for a field for the user's submitted guides called "approved". However, and I don't know when this took effect, but currently guides are displayed even if they have approved=0. So autoaccept doesn't really do anything in that regard right now.
What autoaccept does do properly at the time, is control video uploads. If you have autoaccept=0, you're still able to submit guides (which are supposed to be masked until reviewed, but as mentioned this isn't working), but you can't upload videos at all.
autoaccept is by no means tied to the mgroup field which controls who shows up on the Prominent Members page.