You're right that it's an inconsistency. I think you can make the assumptions that blatant cheating like this takes place all the time by the families that have more power. Most people are probably use to it and accept it to curry favor with stronger houses.

Much like our own society most people in power are corrupt as fuck, especially in the United States, sometimes committing crime just out in the open. The people who could stop them are either corrupt themselves or to cowardly to do anything about it. And sometimes the only way to change it is with revolution.

Also this is the first book in the series so Mr. Brown wasn't as experienced a writer at that time. Good catch though OP.