I imagine it would be hard for renderer to fake all subtle qualities digital camera introduces. Things like "colors too clean", "noise too uniform", "geometric distortion doesn't match any existing lens" would turn up.
In this specific case I think I'd print a fake ticket with dot matrix printer and take photos of it.
I have worked so hard to completely replace dot matrix that I am actually trying to think were I could get access to one and am coming up blank! Many receipts are now the crappy thermal paper that magically disappers from being left on the dash.. Its like magic in the retailers favor...and just about everything else is laser. Where would you get the dot matrix?
In this specific case I think I'd print a fake ticket with dot matrix printer and take photos of it.