(iii)In the case of concerted absence without leave on the part of students, on or before the third day of such absence the names of the absentees will be struck off the college roll. Students absent on such occasions will not be readmitted except under the usual rules of admissions; unless they bring sufficient excuse in writing signed or countersigned by a parent or authorised guardian, and may be excluded at the discretion of the Principal. The decision as to the sufficiency of the excuse will lie with the Principal. On such occasions the college will on no account be closed. The roll will be called as usual.