Genuinely interested to hear other mums' opinion on this, I didn't think anything of it until I saw some headline in a goady crappy newspaper today about leaving a 17 year old (? Wtf?). So we live in a rural hamlet, safe and boring as hell but neighbours close enough to see the house, we work full time and don't really see a lot of the neighbours but we are all friendly and the kids know them much better than we do - the bus stop is a mile away and its the done thing to do for neighbours to pick up any of the local kids in the lane and drop them in the village - just a bit of back story to set the scene!
We are taking eldest kid up to uni in Scotland next weekend (370 miles away) and the 12 year old is coming with us. 16 year old boy has work on the Sunday lunchtime so has chosen to stay home and mind the dog (very soft spaniel who goes NUTS barking if anyone approaches the drive gates). We will be leaving early Saturday morning, stopping over and heading back Sunday so probably home for 6 or 7. He is super sensible and just doesn't party, we said we are happy for him to have mates over but they are typical lovely nerd boys (all boys grammar school kids so not even any girls) and would run a mile at drugs etc (I'm not naive, I was a proper folks away, house party, sick everywhere, spliff burns in the carpets type of teen in the 90s) Its not his style, he is so responsible and practical and sensible and knows he can knock on any neighbours door in an emergency (we will let them know in advance!)
I think this is fine?! No worries at all, he is a great kid and not far off 17 - I have relatives who were in the armed forces/married/parents at his age so it seems ridiculous to worry about him. He works, looks after his brother in the holidays and is an all round good solid boy.
AIBU to just not even worry about this?! He is more than happy with the situation btw, really laid back lovely boy (I love him to bits, can you tell? 
)