I, personally, don't chew gum, but I have no problem with students chewing it in class IF they chew and dispose of it properly. Sadly, when I taught middle school, the 6th and 7th graders absolutely could NOT refrain from (1) popping gum; (2) throwing gum and/or wrappers on the floor; (3) putting it in people's hair. I gave each class the option: dispose of the gum properly or lose the right to chew it. Rarely could a middle school class get more than a few weeks into the school year without me having to ban it. And every single year I had to deal with gum being deliberately put in girls' (and occasionally boys') hair; I cut it out more than once. Worse of all was me having to scrape it off my shoes and pants. Luckily, the problem was not as bad at the high school level, but even college students will spit their gum out on campus or in the parking lot, passing it on to others to pick up on the soles of their feet.