Not true. If you give permission, they can actually tell you. And I have done everything you've mentioned (read original post). Somehow tiny data packets are still being triggered — this should not be the case, and I am not the only person to comment...
Yup, I'm in Europe. Turned off Data Roaming on my phone even before I left Canada and have an e-sim. Last bill, 4 data "incidents". This bill, the same. Get charged $16/day. I feel like it might be text messages or something triggering this, but no o...