If I'm an insider with 100% confidence, I'll take all offers at a certain price as long as I can afford it. Similar story for lower levels of confidence (but still inside info). There won't necessarily be any left for you to copy at a viable price.
> Similar story for lower levels of confidence
therefore, the polymarket betting odds will reflect the truth - even if that info is a secret that nobody else but the insider knows. And if this is the case, then even an outsider could make use of the odds as a source of info which would ensure that market efficiency (which is about the flow of information) is high.
So what's wrong with insider trading again?
The examples didn’t look like they’ve completely emptied the orderbook