The answer to this question can be found at the very beginning of Act I scene 2, as a conversation is continued between Capulet and Count Paris regarding the feud and what has happened between the two households. Having received such a stern reprimand from the Prince, however, the worries of Paris which are obviously referred to in the response from Capulet are downplayed. Note what he says:
But Montague is bound as well as I,
In penalty alike; and 'tis not hard, I think,
For men so old as we to keep the peace.
Thus Capulet considers that both households are under the same restrictions--no favouritism is shown--and thus both know the price of breaking the peace. In addition, older men such as Montague and Capulet, in his opinion, should find it easier to keep the peace than younger, more intemperate individuals. Ironically, he is right, as the rest of the play will testify.