I think some of these statements are mildly, if not beyond, paranoid. I've traveled quite a bit and in some sketchy/high theft & crime areas and never had a pickpocket succeed. Most have been so bad at it it's not even funny. To carry limited items with you is smart, lock up your credit cards and important papers but carry some cash and a single card to carry. A money belt on your body can be way more hassle than the protection it provides. Also some thieves may see you as a larger target for direct confrontation vs pickpocketing. The seat belts while sitting is common sense on a plane but if someone, even a family member, turned to me and lectured me about it I'd think they were suffering from oxygen deprivation. I've been on planes that did massive drops through pockets in the airstream and never been injured. Am I that lucky? I doubt it. Air travel is extremely safe and mostly you just have to use common sense and relax. The more calm you are the calmer people around you will be.