Does Indiana law make any distinction between single edged and double edged knives? I couldn't find anything on it. I did find this, which is pretty interesting: http://www.doe.in.gov/isssa/pdf/FBI-weapons.pdf
Kicking around ideas the other day and was wondering if the "CIA letter openers" are considered blades. They are a polymer knife-like object with a fiberglass core that is intended to be used as a stabbing utensil. I question their actual usefulness in any situation, and it would probably look pretty terrible if one was found on your person during a search. Wouldn't be too brilliant to try to smuggle one into a courthouse or an airliner, but what about just carrying one on your person, or in various other places where firearms and knives are prohibited? This is aside from private property, I mean places where it is unlawful to carry a knife. In the end I think an empty bottle would be more useful, but they are cool in a way.
there is no "double edged" rule.
2: DO NOT EVER ATTEMPT TO CARRY A WEAPON INTO A WEAPON RESTRICTED ZONE. if you do. don't get caught. if you don't, have a plan.
the nonmetallic knives and objects are very useful and comforting to certian people and professions. know your laws, rules, regs, and rights in any situation you carry a weapon into. be prepared for the consequences if you are found in the wrong.
that being said: the nonmetallic knives are generally made and DESIGNED to be a much better weapon than a bottle. never seen a bottle fit a hand like it was designed to in a life or death situation. and those long necks are poor stabbers.