Players considering Stake most likely don't have Pinnacle as an option, or aren't considering them anyways.
In terms of KYC, I agree that Stake is better since Pinnacle has that requirement though I submitted my KYC there anyway since I was tempted by their odds which proved to be a good decision on my part in the long term.
Stake does not have any KYC and that is why I have an account at stake. I do not prefer to play on casinos who make KYC compulsory for without any reason.
If something did go wrong as you suggested... it would not have benefited them in any way to stop coming here, because people tend to turn to the platform where there are the most users to complain about problems with services and sites.
We have seen several threads where people lash out against casinos in the past, when they feel cheated. Stake.com can also not hide from this forums scam accusation section, if they do anything wrong.
https://bitcointalk.org/index.php?board=83.0Stake does not need to do any wrong as they are an established site. New sites look for cheap things to get money but the trusted sites never spoil their reputation.