VOL-42: Commendations

A valid point. My memory is a little hazy at the moment, but I seem to recall thinking that for at least one of these params, a NULL value might get passed into this function, in which case array_key_exists would not give me what I want. (As you can see, I do use array_key_exists for a different parameter down below.) I'm leaving it for now but will be mindful of this in the future.