Not that I like beating dead horses, but...
I did a little more snooping and found that Hasbro DOES have numerous trademarks registered for the word "Monopoly." One of those registrations is for board games. There are others, ranging from computer games to a line of clothing.
These appear to be new registrations - can't tell if they're just updates of old ones or if Hasbro's legal team just did a full frontal assault on the Trademark Office.
If the story you're remembering was 15 years ago, there probably was truth to it then. But there has been a lot of "enlightened thinking" going on with the folks at the Copyright/Patent/Trademark offices since then.
-kurt
thanks for letting me know. I did not know that.