This is incorrect at all levels of real or virtual motorsport, and on two entirely separate fronts.
There's a line quoted by a lot of people who hold onto this belief, from various regulations (currently appearing in the F1 Driving Standards Guide) and derived from the International Sporting Code Appendix O which defines a track. In essence, Appendix O states that the edge of a track should be marked by a 10cm-wide white line on either side around its whole length. The DSR states "for the avoidance of doubt, the white lines defining the track edges are considered to be part of the track, but the kerbs are not."
What these people think this means is "the white lines define track limits". What it actually means is "in any situation where it is otherwise unclear, the white lines (and not the kerbs) should be considered as the edge of the track".
The reason for that is "track limits" are not objective. They are agreed before each session at a race event (usually in the driver's briefing before the first session, with any changes through the event communicated to the drivers thereafter) and can differ from corner to corner (and, in meetings with multiple different series running across the event, series to series). Exactly what the rules are regarding the white line, kerb, and run-off are on a point-by-point basis. This is why you can see some cars in some series extending the exit at some turns but not others, or running the inside kerb at some turns but not others. Anywhere that no specific "track limit" has been defined, the white lines should be considered the edge of the track - to avoid any doubt about where they are.
GT sort-of replicates this. Some corners have insanely generous track limits, some are pixel-tight to the white line. Where it falls down is that no part of this is ever communicated with the drivers.
Ultimately, if you can go there without getting an invalidated lap, it's within track limits.
but it is a proper blast playing that with real people in VR 
