Chalice of the Void creates kind of a unique and awkward situation regarding missed triggers. Under the current rules, playing a spell which would be countered by the Chalice in hopes that your opponent will miss their trigger is fully legal. The only thing that makes it cheating is if you try to somehow manipulate your opponent to missing the trigger.

I think it's important when you're playing a deck that includes cards that have these types of triggers (e.g. Chalice of the Void, Nether Void, Counterbalance, etc.) that you have a firm grasp on the rules and also a proper vocabulary to correctly explain any shady situations to a judge. In the example of the OP, if I were the controller of hte Chalice, I would have called a judge and explained the situation by stating that no verbal or clear non-verbal indicator was made to show the passing of priority after my opponent cast Crop Rotation. Furthermore, my opponent had previously asked a judge if they could "speed through" their actions to circumvent the Chalice trigger and had been advised that they could not. As such, I believe that my opponent is intentionally trying to bypass my trigger, which is using the game rules in a deceptive way to gain an advantage, which I believe constitutes deliberate cheating.