Lived in Ireland for 8 years. I think people would find it a bit strange, yes. IMO, if this is what you usually wear and you’re comfortable that way, then feck other people’s opinions. OTOH, if you want to do this because it somehow fits with your idea of Ireland (and yes, people will presume you think that’s your motivation) then don’t as I’ve never seen anyone wear a kilt in Ireland if they weren’t in a pipe band. Not at weddings either - I think that’s a Scottish thing. No one would have the slightest clue what clan goes with what tartan, nor would they care in Ireland, but I suppose black does make it a bit more modern and more like you were an eccentric dresser rather than a pseudo-Celt.
I have friends who wear utilikilts in England, including wearing one to an office job in London, who’ve reported nothing more than the odd funny look. One did grow up in Scotland, but he’s the one trying to persuade all the other guys to get one, and he doesn’t sound Scottish at all.
I know Ireland =/= England, but there’s a few people claiming it’s a total no-no here. It’s not really. Bit eccentric, but not likely to cause people to faint or draw crowds of children asking where the show is.
On a side note, I met, in Australia, a Scots guy who had brought a kilt with him; he wore it hitchhiking, because he said it was great for getting lifts. Anyone with any Scottish ancestry would feel compelled to stop and tell him where their great-grandma or whatever was from, which he didn’t care about at all, but they’d normally give him a lift as well, and frequently buy him a beer. 
I’m going to stick my neck out here and say Camden? Hoxton? Shoreditch?
One of my recent previous jobs meant me exiting the tube at Old St. and I swear the reason Moorfields Eye hospital is situated close by is because of the massive injuries sustained by innocent passers-by when confronted with adult hipster arseholes and the severe eye-rolling that results.
I wouldn’t have the Aussies down as kilt-wearers but your point stands in general, I’d have them down as more likely a tourist than an ordinary local.
Yes.
Next question?
No idea. London is an amorphous blob of horror that includes most of the South East so far as I’m concerned. Just saw pictures of his work outfit, it was plain black, paired it with a nice shirt. Looked pretty good in my opinion.
I own a kilt, sort of like a utilikilt, and I never wear it except for a couple of places where costumes are welcome. It’s a little heavy but very comfortable, almost air-conditioned, and the pouches hold a lot more stuff than jean pockets. And I have the legs for it, in my humble opinion, and some heavy boots and I’m beginning to wonder what kind of person would even look, much less make a comment in public. Only children, surely, which would embarrass their parents and maybe cause them to grimace.
There’s only one way to be sure though. I’ve got to be bold. If my wife says I can wear my kilt outside, I’ll report back.
Please don’t call it that in Ireland. 
It’s a bum bag.
I love to see a man in a kilt. I’d be very happy to see them become normal daily wear. But the OP asked if they ARE considered normal, and that’s a big 'ol “Nope!”
This is the jist of the problem. Folks will assume you are doing it because you think it will fit in. All of which will put you in the category of idiot American who doesn’t know the difference between Ireland and Scotland, and further thinks that Scotland is still living in the 1700’s Brigadoon-style.
Becuase what I want to know is- would Utilikilts be bad in Ireland, or does the poster just think Utilikilts are silly and should not be worn anywhere.
In Scotland there’s a few groups of “ordinary local” kilt wearers - proper plaid kilts, mind:
- Formal wedding dress, the full flummery
- Scotland supporters at a match- football and to a lesser extent rugby - kilt, heavy boots, Scotland top
- Local eccentrics, probably have a red nose and strong opinions
- A relatively new one is young lads with longish hair, beards and piercings, otherwise dressed like someone at a late-80s Ministry gig. I’ve no idea what subculture that actually is these days, but it’s a strong look
- and finally, it’s not unknown for someone hiking to wear a kilt along with the usual outdoors gear.