What should I have done?

[SPARKLER1]

Went out last night for a few drinks. Whilst in a pub I saw a guy sitting in the corner with a motor cycle helmet drinking a pint of beer. Looking at him he had definitely had a few more than that one pint. When I have had a few drinks I chat to everyone, so I went over to him and said hello. I asked him if he was drinking and driving and he looked away and just grinned.
I told him that I hoped that he wasn't because he was a danger to other people as well as himself. I told him that I thought he was being selfish and that I hoped to god that one day it wasn't my family that he ran into.
Made me so cross. I didn't know what to do for the best. Thoughts of phoning the police crossed my mind many times but then I wondered if I should keep myself out of it as I was worried in case he turned on me.
What would you have done?

[SPARKLER1]

??

[NomDePlume]

Probably nothing, but well done you for speaking to him

[SPARKLER1]

Just spoken to my sister on the phone - she is a policewoman. She told me that there was nothing I could have done. If I had followed him and seen him getting onto the bike and driving off then I could have reported him. Just sitting in the pub there was nothing they could have done.

[LGJ]

I wouldn't have called the police, once I had spoken to him, but if I hadn't spoken to him I would have called the police.

Well done you, too many people these days think that things like this are none of their business, well it would be their business if they had to stand at a graveside and bury a 19 year old friend.

[AnnieQ]

I admire your bravery for confronting him, it's not something I would have had the courage to do.

[SPARKLER1]

Only 'cos I was drunk AuntieQ!

[SPARKLER1]

AUNTIE Sorry AnnieQ Still under the influence of alcohol me thinks.

[SPARKLER1]

Now I have sobered up - I have realised what a dangerous situation I could have put myself in last night. Me and my big mouth.