I'll be taking the LSAT for the first time in October but last month, I took a free simulated PT at the "brother" school to my undergrad university and I chewed gum... and no one said anything. In all honesty though, I didn't really CHEW it, I kind of just had it in my mouth because my mouth gets insanely dry when I'm stressed out and concentrating. That said, if you aren't really chewing the gum, you'll probably be fine as far as distracting other test takers. But if you are noticeably/audibly chomping on a wad of Bazooka bubble gum you're probably gonna get noticed.

@ I have another tip/trick for you to think about trying so you can preserve PTs and problem sets for more practice. Buy a pack of 3-M transparency film, its the stuff teachers used to use for the old-school overhead projectors before every classroom came equipped with a laptop hookup and movie screen. The only downside is that you might not be able to write on them with pencil BUT I know Post-Its makes transparent sticky notes in different sizes and some are almost the same size as 8.5x11 printer paper. Those aren't glossy and you can write on them with anything! (They're also great for taking notes/highlighting textbooks for classes and you can get a lot more money when you sell the book back at the end of the semester) P.S. props to you for thinking ahead, preserving PTs didn't cross my mind until 2 weeks before D-Day and by then I was pretty much done haha