If someone really wanted to sue you, it's pretty cheap to issue subpoenas (<$100). The provider can quash the subpoena on the customers' behalf[1] but I don't know any who does.
In our instance, our service providers received a swath of C&Ds electronically, alleging IP infringement.
Within 24 hours, our various services providers had disclosed personal information, cut off services, blocked payments.. all based on an unfounded email.
The legal system is based on due process. This process should be respected. If my service provider gets a legitimate subpoena, I expect them to react.
However, I don't expect them to divulge personal information and cut off services based on an unfounded email. It's really, really nuts how quickly you can lose your business / take down someone else's business..