You have brought up vaild points.
Air Travel - Prohibited Items also state's
"..The prohibited and permitted items list is not intended to be all-inclusive and is updated as necessary...
TSA has given us confirmation that our keychain is not a prohibited item on-board US domestic flights. If someone got into trouble an they called us we would turn over all documentaion to show the above is true. This information would secure the immediate release of our customer.
Our goal in this keychain was to give good people a way to defend themselves against bad people, flying is a small part.
Devin