OK, part of my response was that I misunderstood what you were saying in this post:
The Umbrella Corporation wrote:
Ignorance of the law is no excuse.
Presumably a Starship Captain, a representative of the Federation should know this.
While browsing through the thread, I had taken the ambiguous "this" to mean that Kirk should have known about Vulcan mating customs/rituals...which he couldn't possibly have known if Vulcans were going out of their way to keep them secret, which is what this episode establishes. (I don't give a rat's ass what ENT retcons into the mix 40 years later, and everything else happens later...Vulcan attitudes about this apparently changed very quickly, given Spock's own openness on the subject in "The Cloud Minders".)
Upon rereading, I realize that "this" was referring to "ignorance of the law is no excuse." However, you then argued....
But if I was T'Pau I might think that Vulcan was special enough to warrant understanding of its customs.
How could she expect an outworlder to understand customs that she strongly felt weren't for outwordlers? Presumably she was chief amongst those who believed that this part of Vulcan society should be a closely-guarded secret.
On the topic in general, I think T'Pau's reaction to McCoy's trick might have gone something like this:
"De neural paralyzer is de neural paralyzer...vhat can be done?"