Cash invoices will probably still work in most jurisdictions, to be recorded electronically after the fact. It's even more work than a handwritten receipt since

Cash invoices will probably still work in most jurisdictions, to be recorded electronically after the fact. It's even more work than a handwritten receipt since the customer would have to be identified, not just what is being sold and for how much, so I wouldn't fault a merchant for taking out a service surcharge for it.