I don't know if Bluebottle is thinking about the same specific people that I am, but yes, there are at least two that I can think of who frequently post in Notebook but never seem to even acknowledge that they have received a correction, much less offer thanks for one. I stopped bothering with either of them. In one case, their last one could be considered to be a scholastic article and it's the only one in that language to have zero corrections and zero comments in the last week. (Excluding a couple of spam items that I reported over 12 hours ago, but which are still there at the time of writing.)
The person has written 8 articles in the last month, 7 of which have one or more corrections from various people, not one of which has even been acknowledged.
What some people seem to not "get" is that there is a limited number of people who are prepared to spend their time doing corrections. Eventually those people will notice the lack of response, and will direct their efforts elsewhere if they feel like they're wasting their time.
I thank each every time. Sometimes they say: "You are welcome!", or even provide an additional explanation. Once I got an excessive help (Angela from the USA -- Greetings and thanks!)
In general, they are all nice people and deserve "Thank you!", for example, this gentleman right above me!
I wish you have real native 'angels'! Don't forget to say them 'Thank you!' This does not cost you at all...