I was over in TX for work, and we had a production system there that was needed online ASAP. So I grabbed a 4G router to allow the VPNs to connect and used one of my spare SIMs (associatedwith my cell phone plan). In 99% of the cases this would not have been an issue, as it's mostly telemetry and the occasional SSH session. Until a geophysicist noticed that it was online and spent the next few weeks pulling down terrabytes of raw seismic data for testing.