to ban drinking in my car?

[completelydisappear]

A group of friends and I are going away for the weekend and it's a birthday weekend and there will be drinking.

I know what a couple of them are like and will probably want to drink on the way down (2 hours drive)

Aibu to tell them they are not allowed to in my car? Last time one of them spilt an alcoholic drink all over the backseat and it's still stained now, and I could smell it for ages afterwards.

I've also never driven there before so I'm a little nervous and I don't want them to be getting drunk and acting silly when I'll probably need their help with directions once I've left the motorway.

Am I sounding too much like a teacher?

Sound I buy a sign for my car that says "Fun Free Zone"?

I wouldn't have it either, they can drink when they get there.

2 drink maximum, like on the Millionaire Matchmaker?

Seriously if they can't survive without a drink en route...

The spillage risk, meh.
The distraction if you are nervous, no, you need to tell them you don't want them to do that.

If they can't survive a couple of hours without a drink you've got bigger problems than a possible mucky car.

They're a potential danger and YANBU. If they argue -even one raised eyebrow - tell them to find another way to get there.

If you need help with map reading and directions then YANBU.

Isn't it illegal for passengers to drink in the car?

Is it legal for passengers to drink in a moving car where you are? It's illegal in most states in the US to have an open container of alcohol in a vehicle on public roads.

I consider that as the owner / driver you are in charge of the car and everyone in it.

I would NOT be happy about this. A drunken passenger/s might be a dangerous distraction. Tell them no drinking in the car. If they don't like that then they either don't come or they get there by other means.