I don't know how much it pertains, but I will tell you about my yearling gelding. He is my first foal and I imprinted him at birth. He LOVES people and is always coming up to the fence, coming up to be haltered, if you clean stalls you constantly have to keep him away from your wheelbarrow, etc.
He did (and sometimes still does) have some mouthy issues where he wants to chew and/or nip in play. I do carry a whip and he knows a "smooch" means he better back away or he will get a swat.
The thing is, I like my horses to be friendly and easy to catch. I am always hugging/scratching them and don't really see a problem with them in my space unless they are being rude (in which case he gets a smooch as a warning and a swat if he doesn't respond quickly).
So I had a friend come over and she thinks he is just awful because he comes right up and sticks his head over the fence in her face. I mean, she thinks I need to send him to a trainer for a month! I personally think a trainer (at $550 a month no less) would be a waste of my money. I would rather save it for saddle training, because he does everything I want. He leads, ties, picks up his feet (including for trimming), lunges (at a walk only because I don't want to injure his joints, he's only a yearling), ponies, wears a bit and saddle, yields his shoulders, hips, backs, sidepasses from the ground, etc. Recently I've been bridling him and getting him used to turning, stopping, and backing to bit pressure. He does all that.
So even though he gets in a person's pace, is that a crime? It really doesn't bother me unless he gets chewy/nipping, and he definitely gets punished for that.
So I don't know. I like friendly horses myself, but some people think it is rude?
I think with a colt it is more of a gray area, because you don't want to teach bad habits, but with my adult horses, I definitely want them to come right up to be haltered and loved on. To me that's part of the relationship. I enjoy it.