Google Docs threw some users for a loop on Tuesday when the service suddenly locked them out of their documents for violating Google’s terms of service. The weird part? The documents were innocuous. The alerts were caused by a glitch, but they served as a stark reminder that not much is truly private in the cloud.

“This shows that Google is using advanced machine learning and other A.I. technologies to examine vast amounts of information in near real time,” Dana Gardner, a leading cloud expert and a principal analyst at Interarbor Solutions, said on Tuesday.

Google Docs is a cloud-based collaborative tool that enables users to create documents and share them with others, and allows several people to edit and comment on a document at the same time.

Depending on whether those affected had created the document or whether it was shared with them, they were stopped from gaining access to the file or from sharing it.