don't know about the rest of the Europe, but here in Estonia (and I'm sure, that in Scandinavia) one could carry puukko openly without any problems, presuming that one looks like having business carrying it. Look like hiker (or look like you work at contruction site) and you will have no trouble at all. Long history will help you 
Of course, going to museums and restaurants is a bit different case. But just walking around should not prove to be a problem in most places.
Still, even I would hesitate to carry you HAK, carry a quick open folder with good thumbstud instead, it might be even faster to draw, if you practise. (how fast can you get your HAK into play?)
While working on construction site (cabling) I regularly went to lunch with my Fiskars on my belt, no problems anywhere.

Of course, going to museums and restaurants is a bit different case. But just walking around should not prove to be a problem in most places.
Still, even I would hesitate to carry you HAK, carry a quick open folder with good thumbstud instead, it might be even faster to draw, if you practise. (how fast can you get your HAK into play?)
While working on construction site (cabling) I regularly went to lunch with my Fiskars on my belt, no problems anywhere.