Black list for words

[tw33kz0r]

May I suggest that there is a black list of words that once deleted from the custom dictionary could never be added to the custom dictionary automatically again. I find I have to go through the custom dictionary every few weeks and I often delete the same typing mistakes. It would be good if once a word has been deleted from the custom dictionary it could not be readded automatically. ie it could still be added by going through the settings menu.