Regarding the rules, CSI is incredibly explicit about this.
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But this isn't governed by CSI rules, it's a WPA event governed by world standardized rules. These rules are far less explicit and significantly more lax.
It does say the shooter "should" call the shot "if there is any chance of confusion". This is very soft wording. It acts more like guidance. If Mika had called it clearly and audibly, there's no confusion. But it doesn't mean he must call it. It doesn't mean it's mandatory. It didn't use the word "must". If the ref is satisfied with the intention of the shot, it doesn't need to be called. A kick, combo, or carom may be considered obvious under WPA as long as the referee is satisfied.