When we create a new site we prefer to create it from a site template. The exported site usually has some users so we uncheck under Global Objects->Administration->Users all checkboxes when exporting. (BTW, I think what should be controlled in the first page under root if I want to export users or not).
I would expect that this would prevent any existing users and theirs data to be imported when creating a new site. It looks like this is also happening and we do not see any users in newly created site but when we run SQL script

SELECT  CMS_Site.SiteName, CMS_User.UserName
FROM  CMS_UserRole INNER JOIN
           CMS_Role ON CMS_UserRole.RoleID = CMS_Role.RoleID INNER JOIN
           CMS_Site ON CMS_Role.SiteID = CMS_Site.SiteID INNER JOIN
           CMS_User ON CMS_UserRole.UserID = CMS_User.UserID
WHERE (CMS_Site.SiteName = N'300510')

(where 300510 is the name of newly created site)
there are all users from the old site in table CMS_UserRole associated with the new site. We need to delete them every time with similar script as above.

Are we missing something or this is not a correct import behavior?

Thanks,

Vlado