Is it illegal (or a crime) to cut someone's hair and run away?

At the very least it would be battery, maybe assault and battery or if it turns you on, sexual assault

It’s assault, in the UK anyway. It was mentioned in my A-Level Law.

I don’t care. GQ for asking a question that made me spill my beer and laugh.

Not if it’s a mullet.

Is this going to be a new sport like sharking or something?
I wanna see you try and get a slice of Kimbo’s beard.

Oh boy… I don’t know, but I sure as hell want to find out now. And not by researching it… That’d be the non-fun way. I’m goin’ downtown Chicago Monday. I’ll let you know how I fare!

umm why are you asking this??....

It would constitute assault, maybe possession of a concealed weapon if you use scissors and possibly robbery if you were to keep the hair since you would essentially be taking something that belongs to someone else..

But whatever else it may be, it would definitely be hilarious