I realize this is a pretty old discussion, but for those wondering what the official position Chris Sawyer takes in regards to OpenRCT2, as official as we're likely going to get anyway, I reached out to Guy Herbert of Marjacq Micro Ltd, the agency that represents Sawyer. Here's the response:
The project has no blessing or support from Chris Sawyer and our view, it is both unethical and unlawful, involving infringements that may in some territories be criminal as well as a violation of Chris Sawyer's rights and those of his licensees - all of which remain reserved.
RollerCoaster Tycoon Classic, distributed by Atari, contains RCT and RCT2 rebuilt for modern operating systems under Chris's own direction.
Sincerely
Guy Herbert
Director
Marjacq
The Space 235 High Holborn LONDON WC1V 7DN
t: +44 (0)20-7935-9499
f: +44 (0)20-7935-9115
http://www.marjacq.com/