The way I view it, Spock knew there was a possibility of a challenge which would lead to a fight to the death. He invited down his off world captain and doctor without telling them this information. T'Pau did not inform Kirk that the contest was to the death, but he accepted to take part in an effort to impress her. McCoy deliberately lied about the medication he gave Kirk knowing it'd simulate death yet not kill him. It seems like they made a mockery of an ancient Vulcan tradition to me. Plus, it'd seem like it'd strain relations with the Vulcans if they flaunted how they fooled the Vulcans.
Another thing that bothers me is that they establish Pon Far is not to be discussed with off worlders in this episode. Then Spock goes on to go into detail about it with a girl in The Cloud Miners. What was the logic there?