Process Improvement Question:

Cashiers spend SO MUCH TIME manually entering coupon barcode numbers into the register, I'm suprised someone hasn't attempted to modify the barcodes so they can be read more easily by the laser scanners. Perhaps technical constraints make this impossible, but wouldn't the scanners still be able to scan the barcodes if the lines/bars were spaced just a fraction further apart, so they wouldn't bleed/fuse into each other on the average home printer?... This would speed up the whole check-out process by several percentage points, I'm sure (even more, on particularly heavy 'coupon days').