Sometimes, drivers have a hard time distinguishing which is which, particularly if it's in a smaller brown paper sack and/or a sack that is placed next to the regular trash cart.
If you are setting out yard waste, you can help by making sure there is some distance between the two or by plainly marking Yard Waste on the sack.
You can even set the yard waste of the opposite side of the driveway, if possible. If you have questions, call MWS, 816-406-9700.