I think one mistake some parents make is they evaluate how their kids are when things are normal and they are at home. For example, thinking how responsible their kids are. Sure they are. When they are at home on a Tuesday night watching TV with mom and dad home. But when kids go to a party, no matter how responsible they normally are, and mom and dad aren’t there, it is amazing what peer pressure can make anyone do.
We did some amazing, criminal, ridiculous, outrageous, embarrassing, never to be spoken of again things in my circle at that age. Yes, we got away with it.
But, I always break out my I was your age once speech. I remind my kids there is nothing they can do or even think of doing that we didn’t do back in my day. In my household, that cuts through the BS quickly. They realize I am not dumb and I was not born yesterday and even though I trust them I know exactly how peer pressure works.
In the OP’s situation, it might be that it isn’t a big party and not a big deal and that is why the OP’s son didn’t tell the parent. Sure, that could be the case. But, I think another parent had it right when he or she posted “what do you think they are going to do play cards?” Exactly. Anything good they can do they can do with parents around. If parents aren’t around you know what is going to happen. Well, you should know.
One mistake can last a lifetime. In my mind, that justifies tough love. If you say no and ground them you get the rebellion stuff and the kids turning you out. That is why you have to convince them of your values so that they think getting puke faced drunk and putting God knows what in their blood stream is as disgusting as you do. A few times a week I hear about this and that local kid on the news who has OD’d on some designer drug of choice. They do not report incidents of STD’s on the news but that is another huge risk factor. One news report from a few months ago was how a local teen meet two guys to sell something, I can’t remember what, but the two guys shot him, robbed him, and then burned his body on a local walking trail to cover up the evidence. That isn’t a party but it is another reason to pay very close attention to what your kids are doing.
As far age, my kids will always be my kids. I will always tell them what to do. Always. They might not always listen but I will try to steer them in the right direction as long as I am alive. I don’t think any parent should apologize for that either. I trust my kids but I trust them a lot more when I keep tabs on them.