Well as far as I know, there is no such thing as a Netflix commercial account. So if they want to be legal, they can not use Netflix.

Same with YouTube. There is a YouTube business account but that is for content creators, making their own content. Not showing other's videos.

Besides the usual suspects: DirecTV, Dish, and Comcast commercial accounts (which are expensive). You could also look at Atmosphere TV for business. Note: I have no experience with setting this up for customers.
https://www.atmosphere.tv/