Welcome to the forums.
I am a LEO in Knoxville, so hopefully I can answer your questions about Tennessee knife law.
The law in Tennessee is pretty simple, anything with a blade over 4" is considered a weapon. As long as you have a knife with a blade under 4" then you have no worries. You can carry it any way you wish.
That isn't to say that cities can't have a more restrictive ordinance. Knoxville mimics state law. I'm not sure about Nashville. It's probably the same but I'm not sure.
The best thing to do, IMO, is be honest with the officer. Depending on the nature of the call I have removed a knife from a person and held onto it until I'm about to leave and then I give it back. Don't do it often , but I have before.
Their has been a debate on blade measurement for quite some time. I measure the blade length as the sharpened portion of the blade. I have heard horror stories on the forums about officers measuring the blade from the tang. I believe this could easily be defeated in court though.
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