DC are 7 & 5. Normal bedtime is 7.30pm. DS1 reads for anything up to 90 minutes after we have gone downstairs, ds2 tends to be asleep a lot earlier then that. Since the light nights, and especially since it has been so hot and sticky, they have been noisier after bedtime, with lots of toing and froing between the two rooms. However, we/I (h partly moved out now) tend to ignore this as long as not too rowdy - dc do not seem over-tired and the focus is on them during the day, so evenings are precious. We usually go camping (is booked this year, and the plan is to go ahead, despite separation 
) and bedtimes go out the window then, but otherwise, unless there is a special reason, we stick to them and dc are fine with it, I think.
Tonight a friend, as planned, came round at 7.30 to drop off a pet I am looking after for them while they are away. They had brought their dc - the same ages as ours. They were shocked to find ours in bed and the mother, in particular, made several comments about how she expected ours to be up since it is the holidays. Tbh, even if they had been up, I would not have wanted them getting hyped up at that time in the evening, no way. Both parents were there, so AIBU to think that one could have stayed at home with the dc, or that they could at least have checked before bringing the dc round?
They spent a really awkward hour here, constantly 'shhing' their dc with pointed comments about ours being in bed etc, so that I ended up feeling embarrassed for my dc - like I have shown them up in front of their friends. They were still awake, of course, and when I went up afterwards, they were in one bed giggling about why their friends had come round 'at night'. I wonder why they just didn't come down, but they didn't.
As a side issue, am I the only parent who tries to maintain normality during the holidays - ds1, in particular, is noticeably 'older' this year then last, iyswim.