They do, of course include disclaimers that they're not offering legal advice. I think attempting to combine that with a parametric search might be more legally risky, as it makes a specific statement of "X knife is legal in Y jurisdiction", which people might act on without further interpretation or analysis.
https://www.akti.org/state-knife-laws/
https://knifeup.com/knife-laws/
They do, of course include disclaimers that they're not offering legal advice. I think attempting to combine that with a parametric search might be more legally risky, as it makes a specific statement of "X knife is legal in Y jurisdiction", which people might act on without further interpretation or analysis.