People were using the plans to make outright FT copies. Customers were buying kits that had all the copyrighted FT branding, but were missing parts, burned, etc. The foam board wasn't even Adams foam board. Caused a lot of trouble with customer service as well as monetary loss when some of them were sent replacements from FT.
There is an FT vlog that was made more than 7 years ago featuring a copied FT design. (Not FT branded) It was long before the outright FT branded knockoffs happened.
12 min. vid. The knockoff feature is in the beginning, middle and end of the vid.