Maggie grabs my nose, and uses it as a handle to turn my head with her beak when she preens my eyes... She's been doing that for years now. I never saw any harm in it.
Of course, she isn't lunging at me when she does it. Her wings aren't up and flip flapping. Her shoulders aren't hunched. She isn't leaning forward with her beak open in the "fixin' to launch at you" posture... and she doesn't have that eye pinning agitated look on her face... This is a young "excitable" bird, who probably didn't belong on a shoulder yet...
I'm guessing Fargo doesn't either, when he uses your nose for a beak hold while shifting position or what not... Fargo's completely calm in the photo you posted. He's just doing the same thing with your nose that he does with fingers and toes... (They are so tactile with their tongues!) And if they're bite pressure trained, and trustworthy, I don't see anything at all wrong with it. I play with my birds all the time face to beak... and one of the reason's I do that is so that they don't freak out and apply bite pressure if someone comes up to them and gets right in their face... so I don't think it's crazy at all. I think it's smart.
When you look at the expression on this bird's face, he ain't playin'...
She is wincing, and beginning to scream... Even if it's just a pinch, when it's your face, THAT HURTS, AND IT IS UPSETTING!