You can hope your child doesn't become friends with this kind of child......or isn't the one who leads the others astray. Funnily enough, most parents see it as their child being led astray rather than doing the leading.
Op, do you think your child is easily led? Some children, even from an early age jus seem to walk towards trouble. It's good to be aware of the reality of what our DC are like, but even then, they can do things good and bad that totally surprise us.
A key thing is to know what is going on socially and maintain control. I know parents who have very clear rules which aren't popular with their kids but have helped protect them from some of the .opportunities' that might arise. So, not letting their children stay overnight at parties, or only overnight anywhere after talking to the host parent, never when there are mixed groups staying, never if alcohol will be allowed. They always collect their children rather than letting them make their own way home or be brought by others.
You'd be surprised how many parents of teenagers let their children go to parties where they don't know if an adult will be present, if alcohol will be available, who will be there......Lots of parents will let their children stay overnight in locations without knowing these things either. Some of it is naievete on the part if parents, sometimes not wanting to be unpopular with their children, sometimes a bit lazy.
In the end, it's you abs parents who have responsibility and biggest influence over your children. It really won't really be down to the school if a child goes off the rails, but the actions of the child themselves and also the input from parents.
Teenage years can be tricky. Some children are compliant and don't seek to push the boundaries. Most will at some point and it's good to have a clear idea of what you expect and how you're going to play it. In my view, letting kids below 16 go to overnight parties or parties with booze and no adults present just isn't a good idea. Lots will disagree, but it seems a simple way to protect your child. There are lots of ways to have a good time. And parents can sometimes work together to help groups of kids - agreeing together to no parties without adults, no or limited alcohol etc. When parents agree together and stick to it, it can be much easier for both the parents and kids.