I've guess they've got a point about the tools. Discretion is the key, as long as you don't have metal detectors and the likely hood of a search is low I would carry a few tools. But don't flash them or use them outside of an emergency. It also depends on the context, put next to a first aid kit (in a bright red store bought case or pouch with the white cross on it) and a space blanket, they suddenly seem a lot less threatening. Just as important (possibly most important) is your reputation with your teachers and administraters. If they know you're an upstanding student (and it sounds like that's likely), you'll face far fewer inquiries then you might otherwise. Your reputation can be your best armor.