Why do I get so many hints for people who are unrelated?

I don't know for certain, and would certainly like to be corrected if I'm wrong, but I have a vague memory that hints are provided for relatives of people on our Recents list. So if you have looked at the profiles of people you are not related to and in that way put them on your Recents list, you might start getting hints for them and their relatives. Also, you are not related to in-laws, so if you have been working on the spouse of a relative and so have that spouse on your Recents list, you would start getting hints for that spouse's relatives even though you are not related to them.

If you have just noticed this recently, it might also be related to this reported problem: