I use friends and family as sample data for unit/integration tests.
At a previous job, I tested an automated email system by scheduling fake events for various US presidents. I’ve long left that position, but I never cleaned up the test data. Every month I still get a reminder for Nixon’s upcoming reservation at the Watergate Hotel.
Happened at my workplace. An phishing email went out to test how likely people were to click the link.
Anyone who clicked the link had to take phishing training. Anyone who forwarded it to our internal “hey this is a phishing email” service also had to take training… because the internal service would automatically click the link.