Sec. 15. In addition to the grounds specified in section 14 of this chapter, a student may be suspended or expelled for engaging in unlawful activity on or off school grounds if:
(1) the unlawful activity may reasonably be considered to be an interference with school purposes or an educational function; or
(2) the student's removal is necessary to restore order or protect persons on school property;
including an unlawful activity during weekends, holidays, other school breaks, and the summer period when a student may not be attending classes or other school functions.