Now that it's fall, I carry my sanitizer in the coat or jacket pocket - it's handier and cleaner that way. But when I kept my sanitizer in my bag, I always made sure I put it in the catch-all pouch and make sure I zip it up, lest it leaks.
I actually had a scare once. I used the sanitizer, was too busy to put it inside the pouch, so I just tossed it into the bag. A few seconds later, however, I thought to myself, "No, you should do things properly." So I reached into the bag, grabbed the bottle, and realized that somehow, the cap became loose! In a few minutes, it would've leaked everywhere inside my beautiful Givenchy - all over my wallet, my notebook, my phone, you get the picture. After that, I always made sure the sanitizer bottle is closed tight.