The issue is that the definitions of "gravity knife" and "switchblade knife" covers virtually any knife you can open with one hand. The spring assisted folding knives, and other easy open folding knives, that are so popular right now, are illegal in Colorado. CRS 18-12-101(1) (e) "Gravity knife" means any knife that has a blade released from the handle or sheath thereof by the force of gravity or the application of centrifugal force. Any knife that can be flicked open is included. In Colorado a folding knife really has to require the use of two hands to open, to be legal, like a Swiss Army knife, or a like knife that has a very strong spring keeping the blade in the handle.
This is why getting rid of this stuff makes so much sense. Colorado's knife law is stupid, and is out of step with knife technology, and with the rest of the US.