There is also what I refer to as "Deconfirmation Bias" working in his favor. All characters such as ATs and such got disconfirmed the minute they were shown. Nintendo even sent a note to IGN and other places after the Robin trailer to tell them that Chrom definitely wasn't playable to "clear up confusion."
Meanwhile Ridley's status has yet to be disclosed. So all of this begs the question, if Sakurai/Ninendo clarified all of these other characters' disconfirmed status immediately, wouldn't they have done the same for Ridley, so as to "clear up confusion"? Since they haven't, that can only mean that Ridley is more than likely playable, and with the exception of G&W all veterans and newcomers have not been shown
directly until the formal announcement of their playable/non-playable status has been made, which would explain why we were only shown Ridley's shadow in the April Smash Direct. (On an unrelated note, G&W being shown but not confirmed makes me think that he may
not return this time around).
(Credit to @
WingedSnagret for first mentioning the disparity between Nintendo's actions with Ridley and the most recent example of their immediate disconfirmation/clarification of Chrom's status in Smash 4.)