Sorry was out all day yesterday and just getting to reply. And please note I am referring to mostly Post 1800 Profiles where there is a greater wealth of records readily available than those from previous times. Earlier Profiles are a whole different ballgame to me.
I decided to run various test searches on one of the Profiles I received the 631 Error on and discovered that whether I had put in their Death Location Field Unknown, United States or left it blank and each was marked certain or uncertain for each search, the Profile showed up in a search using First and Last Name and using the Date range of + or - 12 years and not using actual known dates for birth or death, but within the designated parameter, he showed up. This includes using a blank, Unknown or United States in each search as a parameter as well. He still shows up. And that was a bunch of searches...LOL
My only problem with my suggestion to me was if by using Unknown would this interfere with the WikiTree search engine and apparently it does not.
Yes, the LNAB field must be filled or a Profile cannot be created and Unknown is the WikiTree Policy as a standardized naming convention. Using Unknown here does not negate the person had a LNAB birth, just at the time of the Profile creation no known source could supply this fact. I am just expanding on this precept.
I feel using Unknown here lets a future viewer know that at the time of the Profile's creation or my last update, I had not found this fact in my research. It's not blank because I am new to WikiTree and don't understand how important locations can be to future viewers/researchers or I added the name from a Find A Grave cemetery listing or some book of "Historical" biographies and did not bother to check or add other sources. It is Unknown because my research did not turn up an actual location.
Yes, I could put in the name of the country I believe they died in and would probably be correct 99% of the time. However, that would still be a guess no matter how sure I am and should be marked uncertain accordingly. Therefore, in doing so I am stating I really don't know where they died and in essence by saying or inferring I don't know, logically the place of death is Unknown at this time.
Back to the gist of my question then, if a blank or using country name and marking it uncertain infers Unknown as the responses have pointed out, then why is stating the logical Unknown an error as it does not seem to cause an error in searching the database? JMHO ;)