I've heard it argued that if a LEO can see you've got the knife, then it's not "concealed".

Coming home from hiking about 2wks ago, we stopped at King Soopers to grab a few things for dinner.

I was carrying my Glock 34 and Trace Rinaldi TUK (~4.1" fixed-blade). I adjusted my shirt so the Glock was still concealed, but the knife wasn't.

The LEO posted at the front door either didn't notice, or didn't care.

I've also experimented with "open carry" with my BHP, but I feel really self-concious / dorky so I've gone back to concealed.

Mike