That is quite complex I think. In my office I usually have a couple of knives on my desk to play with during idle moments. My partners and coworkers don't take offence. The know me and my quirks and the largest knife usually around my desk is a Nimravus, not the Brute.
My girlfriend is not very comfortable around my knives and neither is some friends and family, so there I keep a lower fondling-profile. When alone and reading or watching TV I will often have several knives around for fondling and playing. Generally I think, it is not considered polite to whip out your knife in public if you have no cutting to do. I don't always care that much though - depends totally on the situation and the people around.
Regards Jan