Debates aside; I have been told that there used to exist a message either in Lego catalogs or inserts in boxes that reads as this:
The word LEGO® is a brand name and is very special to all of us in the LEGO Group Companies. We would sincerely like your help in keeping it special. Please always refer to our bricks as 'LEGO Bricks or Toys' and not 'legos.' By doing so, you will be helping to protect and preserve a brand of which we are very proud and that stands for quality the world over. Thank you! Susan Williams, Consumer Services.
Does anyone have a photo of this insert or catalog text that they could share?