My last parents evening, I made a lot of hints. 'Oh, thanks so much, it was so useful....Oh, we've got our maths appointment in five minutes...' the teacher in question Did Not Take The Hint. It was so annoying. The maths appointment came and went. Talk, talk, talk. If it was useful, great, but it really wasn't, it was basically talking about events which had happened but she hasn't been involved in (in fact, which her yeargrop hadn't been involved in).
There's people like that in all walks of life. Some are teachers, some are parents (although, as there are more parents than teachers, presumably more parents will be like that on the day?). And however much you hint, some people will never get it.