When Greg and Riley drive up behind the garbage truck and exit their Denali, Greg is seen wearing a tan T-shirt underneath his CSI vest; Riley is wearing a sleeveless shirt underneath her vest. They walk up to the truck cab, attired in the above clothing, and ask the driver to dump his load. However, as soon as the load is being dumped, both Greg and Riley are seen wearing their dirty-work coveralls. There is no way that they could have put on their coveralls in that very brief period between talking to the driver and the load being dumped out.