As I suggested earlier, if the keywords which you add later (be it white keywords or black keywords), are in no way related to the existing keywords (be it white keywords or black keywords) in that campaign (or ad group) then do expect account suspensions. It is quite simple to understand. Nonetheless, it is your prerogative to be adamant about accepting what I've mentioned and that is fine, because it is your accounts that'll keep on getting suspended, due to you keeping on doing what you are doing (with the keywords, as explained above).