It is important as to whether the issue is a controlled document or if it is data collection. Changing controlled documents with white out - that becomes interesting. Did you change all of the copies? Did it need rev-ed? Some systems allow "temporary" changes as long as they are initialed and dated. Usually that will pass muster (do what you say....). But, if you see a print on the floor with white out and no initials - you have no idea if a person with the appropriate authority made that change. That would not pass.
As far as fixing data collection mistakes, you may pass an audit if you allow white-out in your procedures. Firestone may have not liked to put data on the overhead in court looking like that....but, that is beyond the discussion here.
Nothing is ever illegal until you get caught. Pencil is never a problem until one sheet gets smeared and a customer or third party auditor gives a finding for illegible document, and you need a corrective action. Until then, you are free to use crayons if you wish.