A question came up recently regarding changing Unk to Unknown. The Unknowns Project does actively work on finding better sources for the variant spellings that we have found so far. If we are unable to find the correct Last Name at Birth (LNAB), we either change the spelling to Unknown or ask the profile manager to do so.
One of the responses to the question expressed concern that making the change to Unknown could cause extra redirects. I have verified with the Team that, in this case, the extra redirect is appropriate because "Unknown" is treated differently by the internal search engine.
When profiles have the surname Unknown, they will show up in searches where a married name is searched, but there are profiles where the surname is not known. In other words, if you have "Elizabeth (Unknown) Martin," and you search for "Elizabeth Martin," profiles for Elizabeth Unknown are included in the search, whereas profiles for "Elizabeth Unk" or "Elizabeth MNU" are not.
Unknowns Project members always try to find a valid surname before changing from any of the Unknown variations. Only when it becomes apparent that the unknown name is not going to be easy to find do we go ahead and change it so that the profile is indexed properly for searching.