Given McG's exposure and the money he has, i'd expect prosecutors to line up for days just for a shot at that.
And regarding the burden of proof, two things
1) He did so in a bar and from what i've read, this ain't the first time he'd done it. Chances of witnesses are not low.
2) Prosecutor doesn't even need to win. It's in McG's best interest to settle. UFC doesn't want to touch that sort of publicity with a pole.
My question was more along the lines of him being a professional fighter. In many jurisdictions they consider that along the lines of assault with a (deadly) weapon. It's no joke, which is precisely why i'd expect the affected party to have his phone ringing by lawyers all day begging him to press charges.
Funny you mention that. I was in Dublin for Argentina's game. We touched the subject a few times and, at least the overwhelming majority of the Irish i spoke to though, to my surprise, that he's nothing short of a moron. This is anecdotal evidence of course, but i asked them if this was just them or if this was a generalized view and they all agreed it was the majority. The basic argument was that the Irish, cultural wise, don't like anyone who brags too much. A bit of banter is welcomed course, but after the Aldo fight he lost the plot and the character eat the man.
This is of course, again, my very short lived experience. Happy to be corrected.