I'm not sure that's true. There are wealthy, powerful men who can pay any hourly rate for sex and who are practically above the law in many parts of the world. It would be a mistake to assume that some of them wouldn't assault an escort in the not inaccurate belief that they can do whatever they want with impunity.
It is backed up by the author's analytics, though. Perhaps there are valid criticisms about her sampling methodology and the sample size at the very high end, but it's a good start.
I did not make any such assumptions, and I did not say itβs zero risk, I simply said that the risks are likely to decrease as hourly rates go higher.