Most European member state laws provide that the failure of a party to claim or enforce its rights does not automatically qualify as a waiver of such rights. Also, if a party does ‘waive’ its rights in a certain situation, member state laws will not easily presume a blanket waiver.
Waivers. A failure of a Party to enforce strictly a provision of this Agreement shall in no event be considered a waiver of any part of such provision. No waiver by a Party of any breach or default by the other Party shall operate as a waiver of any succeeding breach or other default or breach by such other Party. No waiver shall have any effect unless it is specific, irrevocable and in writing.
The above clause specifies what may or may not be the consequence of a party’s behaviour or (informal) remarks.