Mmm yes I thought that also, The Zork titles are the only ones that are in the public domain. "Activision Studios owns and maintains full copyright on all Infocom games. With the exception of the first three Zork adventures no Infocom game can be legally "downloaded for free""
I think the OP might have to trim a few titles.
http://www.csd.uwo.ca/Infocom/faq.html#PIRATE