I can’t put any numbers to this, but yes, it’s probably the case that as the ATV increases the dispute rate also increases, and probably particularly rare in the food service industry.

In my experience it can be rare even with an ATV in the thousands of dollars, but it’s still (unfortunately) a non-zero risk.

It’s the card present/card not present (ie online, phone, etc) distinction right?

Yes - it's hard to automate because it's offline, it's higher risk because you have to show your face, it's usually low value products, and if there's any issues people usually go back to the cashier and then void the transaction - removing a large part of refund costs.