Who Is at Fault?

Here is the scenario:

My (male)mate and I are at the pub, as we often are on Friday evening. He has consumed copious amounts of beer, as he often does when we are at a pub on a Friday evening.

Along comes a girl he was dating briefly this past summer. She is beautiful and charming! He is very drunk and tells me, please don't leave me alone with her(She really is femme fatale sort - NOT) as he has been dating someone seriously the past few weeks of whom he seems to be very fond.

Being the ever-faithful friend I am, I stay a bit knowing his weakness for beautiful women. However, I do begin to feel like the 3rd wheel and say my good byes leaving him to fend for himself. Ultimately, we are responsible for owns actions, right?

On my way to my car, I run into a male friend, told him the scenario, laughing as I am a bit amused. He then said 'If something happens, it would be her fault.'
At first I think he is taking the piss. Then I realised, he isn't. As I have a very feeble mind, I enquired as to how is she at fault?
He claims she has complete control over situation.
I stare at him blankly.
'She can say yes or no.'
I said 'He should keep his trousers zipped as he is the one in relationship. It is not her duty to ask him if he is.'
He claims it will be her fault if they consumed anything more than dancing that night.
I say 'RUBBISH'.

You say?

edit: typos, typos, typos