I was responding to the question "how would they know if I lied", not justifying whether it is fair/legal to pay remote workers differently based on their locat

I was responding to the question "how would they know if I lied", not justifying whether it is fair/legal to pay remote workers differently based on their location. I agree that a customer-facing scenario may be rare for a programmer, but it is easy to imagine other scenarios playing out. Like your manager or colleagues asking to meet up with you face to face. Or needing to have documents or hardware couriered to your address.