My thing with Star Trek novels is...it can ALL be canon. ST is all about alternate timelines/dimensions etc, so why can't it all be considered canon?
I'm not so sure about that. While I've no doubt that there's a routine amount of less-than-honorable ocnduct among Ferengi, it would seem that it's not in their best interest to flat-out cheat all the time. Because if they do that, word will get out, and they'll lose customers - something no Ferengi wants.