Point is, there's no way to search for Mary Jones and find the Mary Joneses who don't have Jones in any of their name boxes, either accidentally or deliberately.
This matters for finding duplicates, if somebody imports a profile with only the married name.
And of course a lot of the maiden names are Unknown. So if you don't want to show Jock Nock's wife as Jean (Unknown) Nock, she'll have to be Jean (Unknown) Unknown and you'l never find her.
if you don't want to put a married name in the CLN box, you can add it as an OLN. Then it won't appear anywhere except the main profile page, but it'll work for search purposes.
But that brings up the other oddity. The OLN doesn't appear in the search results, so Mary (Smith) Smith aka Jones will only be listed as Mary Smith. If you don't know about this, you might not realize that she's the Mary Jones you're looking for.