I suppose you are right that asking for a number/assurances is different to demanding them as pre-conditions.
We could be the ones offering them as sweeteners to reduce the financial figure.
As for basketball there are only 16 players on the team with 5 players on the court so their influence is greater.
I cannot think of any NFL player with this type of power as they mostly receive toilet paper contracts.
BTW, feel free to correct me if i'm wrong as i do not pretend to be an expert on American sports.