I don't think she was stating that because she thought you needed warned not to get violent but rather because she'd said "within reason" and was clarifying what she meant by within reason so that you didn't think within reason meant anything other than if a client is violent. Being clear just eliminates any confusion. If she had not explained what she meant you could have assumed angry behaviour isn't allowed, criticising her isn't within reasonable behaviour, crying isn't within reasonable behaviour etc etc etc.