Question about Chalice triggers and Mana Manipulation.
I'll just chime in and agree with Mark Brown & Joe Klopchic.
First, as Mark said - no ‘O’ is forthcoming - because, as Joe said, this can only be determined by the Head Judge, at the time it happens.
Also, I'll go a bit further than Mark's skepticism re: “hoping your opponent doesn't know Opt is 1 cmc”; I don't think this would ever happen, as described. While Mark's right that players try to run something by a Chalice, in hopes of a Missed Trigger, this sequence just isn't believable. (And sure, I know it might have actually happened once … it still isn't believable!)
Finally, as Jasper pointed out, the player would have to know they're breaking a rule for this to be Cheating. As described in the original post, the “clever” player is Opting for a line of play they hope will work, but not something they hope they'll “get away with” - i.e., they aren't breaking any rules, in their mind.
d:^D