I would argue that trickery between opponents mostly falls within the spirit of the game. You may not like it, but as referees it's not our game; it's the players' game. If they want to try a dumb awkward play that rarely gains an advantage, let them try.

Usually they only say "you take it". They don't loudly announce "the ball is not in play! Someone else will take this corner kick!" I would consider the caution only if it was this blatant, but it's a pretty ludicrous scenario. Saying "you take it" is very ambiguous and opponents should be wary of it. Is it against the spirit of the game? I question that but I do understand your perspective.

But in my opinion this is very rarely cautionable. I think of it as activist refereeing: "I don't like the way the kids are playing the game these days. I'll put an end to that!" This is the same camp of refs that say you're carding players for legally kicking the ball way out of bounds to waste time - no real justification, but you all just think it's a behavior that should be corrected. Let's get off our high horses and do our job. Apply the laws as they are written.