I think my friend Paul makes some excellent points - and as one who has nearly gone off watching the results of his always enthusiastic testing of the "limits" I can vouch that he in nothing if not an ardent racer - but one I'd always happily share a track with.
The issue surely is that very few of us know our "limits" until we have exceeded them - I'm fairly sure that most of the time I've not been very close to my or my car's limits - but equally on occasion have gone over - thankfully usually without "hilarious results" - usually just some time lost. At some circuits of course Mr Palmer provides sensors so that the CoC can present you with a picture of just how you have exceeded those limits
The trick really comes in determining where exceeding a track limit is deliberate and results in obtaining an advantage without any risk - eg the afore-mentioned first chicane at Croft where the floppies are routinely flattened and the corners thereafter straightlined, compared to Oulton's Britten's chicane where you can kerb-hop at some risk to your suspension, or a little later, Hislop's where not staying on the black stuff can lead to meeting some pretty hefty tyre stacks, so nobody "chooses" to cut there - the chicane "escape route" being a better option
Circuit design and furniture can obviously help enforce proper behaviour, although I know consideration of the risk to the two-wheel racers is another factor.