Clubs in the Championship have the freedom of choice over whether to take the knee before kick-off and it's been that way for some time now.
As the new season began here, Watford continued with the gesture but Sheffield United's players remained standing.
By the end of the night, it was the home side who'd showed why they deserve to be considered among the promotion favourites thanks to Joao Pedro's winner from a lightning counter-attack.
Match Facts: Watford vs Sheffield United
Watford (3-4-3): Bachmann; Kabasele, Sierralta, Cathcart; Sema, Cleverley, Kayembe, Kamara; Sarr (Manaj 81), Joao Pedro (Gosling 87), Dennis.