So I just walked into The Bannered Mare and an NPC who calls the player character a milk drinker which can lead to a fight was in there.
I never knew it could happen in cities.

Once I saw one of those NPCs inside the inn in Falkreath. It's hard not to trigger the other NPCs around whilst the fight.

I accidentaly killed Mikael so I had to reload the save. I never usually load a save if an NPC dies but I cant have Ysolda hating my character.

It's amazing what you can discover when you're not in Helgen most of the time.

Paralysis poison; let the other inn occupants chop up the brute.

I am already at 57 hours 39 minutes and 5 seconds with my current character. I have only done 13 quests and 44 misc quests.

I probably have 500 hours in helgen. I have over 4,400 hours. so basically 3,900+ hours playing skyrim.

im always been called milk drinker especially in windhelm an i never get in any random fights.

I get in fights but those are ones i start on purpose after all a vampire needs to eat an with so many guards their irresistible

My favourite "milk" encounter, was when I visited Sinding in Falkreath jail and a Redguard challenged me.

I once slew and elder dragon along with a couple of master vampires by myself, orc walks past, called me out as a milk drinker....the only option at that point was to remove his head

NPC LOGIC

I get called "milk drinker" by random Argonians, Redguards or Orcs patrolling the roads of skyrim...however, they never end in fistfights. instead, they actually try to take my head off (but instead I end up taking theirs )

I get them all the time. Most recently it was in the Winking Skeever.

The other day in the bar in Solitude, there's a guy in there with all mis-matched armor who I noticed right away, because he was wearing a Daedric cuirass!
Now there's something you don't see everyday...
So the bar is full of people (including kids) and we're standing right beside Lisette who is singing away, and the guy calls me a milk-drinker who should go home to mama.
I slunk back into my seat and wept...
(I was so afraid.)

I remember my long-since retired Nord warrior having a memorable evening at the Frostfruit Inn, where she beheaded an idiot who called her milk-drinker. Everyone else was remarkably cool about this incidence. I guess it was just another Tuesday night in Skyrim...

I never seen that random encounter