Fair enough, Bullfrog, you had no need to mention it to Donald, seeing that he had mentioned them before.
On the wider point, I don't agree with any general position that there is no need to mention them on the grounds that they are there in front of people. For one thing, I never notice them when I go to that screen. And don't tell me this is unique to me. For another, quite a few people who post here don't appear to notice them. And a third thing: neither do they appear to notice the state of their own posts, considering what is so often either near illegible, doesn't make sense or has key information missing (such as how many words there are in the answer). So the hypothetical noticing may not be that relevant or actual in a lot of cases.
Final thing is that posting reminders of the instructions and where they are is helpful in the same way that posting the number of letters in an answer is helpful to some people reading the forum but not having that particular crossword in front of them. It is of course not necessary for those who do have it but that doesn't stop us asking people to post them in order to be helpful to others on the forum.