I also recall that a couple of years ago the TSA tried to adopt the EU standard 6cm blade rule
The flight attendants' union lobbied hard (and successfully) against the change, forgetting entirely that flights TO the USA are - solely due to 6cm blades (about the same length as the metal knives provided with meals...) - horrendously unsafe, whereas flights FROM the USA (where guns are regularly found in passengers' hand luggage) are as safe as houses...