Above. This is a cheap plastic blind.
Below. This is a window covering.
Back before I represented developers and builders I don't think anything caused more petty squabbles at closing then window treatments. On either side.
Even though our MLS offer to purchase clearly states that window coverings stay with the house yet the homeowner took said window coverings and left the example at the top of the page, a plastic blind.
An overly demanding Buyer who was promised window coverings thought that promise entitled them to purchase what ever at any expense.
A good agent, on either side, should be able to defuse this situation either by explaining the signed contract to their client or to the other agent involved.
I don't think I ever lost a deal over window coverings but it may have contributed to my hair loss (pulling it out).