@Kaarme While that isn't a bad idea, there's just too many options when you're the one doing the poisoning and not all poisons are distinguishable from food by smell, so they'd be putting a lot of time and manpower in to training dogs that people could still figure out how to slip stuff past.
The main character pointed out why the system they're using is flawed too, but for the most part someone trying to poison a court member is going to go for the quick acting stuff. The slower acting poisons can be detected by symptoms, like what happened with the make up, and stuff can be done about it before it can kill someone.
Since these people are in the habit of "employing" people that were literally kidnapped, they probably aren't lacking for metaphorical canaries to bring into their metaphorical coal mines, and they don't even have to bother training them for anything. They just stuff food in their mouth and wait a little bit.
@moonlight00 When I read it, the "such a waste" thing seemed to me like she was irritated/exasperated that a man was so pretty she thought he was a woman. Y'know, 'cause she's a freckly two by four herself, and insisted she didn't mind not being more attractive but it probably irks her a bit. Suppose it could be either thing or both though.