monday is formal dress
the rest is t-shirt with collar

but i everyday also t-shirt with no collar xD
COIT lecturers are not that strict, my 4 years studies there, only 1 lecturer that require us to have proper attire
mostly it's the guard that causes trouble, well.. u can always enter coit using side doors

about COE.. well.. bcoz it's near admin, so the lecturers and guards will be more strict.. u need to wear proper attire or else they won't allow u to enter.