Exactly.  You can get it right from the horse's mouth here:

https://twitter.com/TwitterSafety/status/918502629679939584

"We have been in touch with Ms. McGowan's team. We want to explain that her account was temporarily locked because one of her Tweets included a private phone number, which violates our Terms of Service. 

The Tweet was removed and her account has been unlocked. We will be clearer about these policies and decisions in the future.

Twitter is proud to empower and support the voices on our platform, especially those that speak truth to power. We stand with the brave women and men who use Twitter to share their stories, and will work hard every day to improve our processes to protect those voices. "