Clear left, right?
Could it be that someone is recognising the ambiguity of the English word "right"?
Presumably in the same list of standard callouts the copilot is being asked to call "clear right side", rather than "clear right"? The latter is capable of being misinterpreted as "clear...right?".
I prefer the expressions left-hand and right-hand. Even better are the old-fashioned terms port and starb'd, but they don't teach sensible things like that any more...
Well at least that's a stab at a reasonable explanation. Thanks. And yes, the FO call is 'Right-side'. Although actually, I'm not sure if its hyphenated. I better rush off and dig out my FCOMs to check that.
Just kidding.
Clear LEFT.
I'm a rebel. So fire me.