Tin foil hats are references to assorted crazy folk who in days gone by, used to cover their heads with tinfoil to prevent the influence of government (or extra-terretrial) mind control waves.
To suggest that a post is a tinfoil hat post, implies that it is a paranoid delusional conspiracy theory or a technically ridiculous bit of drivel unworthy of serious consideration.
I agree with your definition.
Ipso facto,"Tinfoil hat"="OWK"