Most users can not see anything from admin tree, but still we are loading it nearly on each page, this caused very many extra php includes.
We could store a flag in session which would indicate that user can not see anything from admin tree and then we would just skip loading of the admin tree completely.
This could help with memory and CPU load.
-50 file includes for each student on each page
-4MB in 64 bit OS on each page for students