National and international legislation is defining demands to the packaging design. EN13428 has as a criterion that the packed product has to comply with legislation. Such legislation can be UN-requirement for transport of dangerous goods, child protection, easy-opening for elderly and disabled, specific labelling, dimensions and packaging materials, etc. etc.
Many companies believe that such legislation can be an excuse for not fulfilling the requirements in EN13428. BUT this is NOT the case.
You still have to document the assessment that you have reached critical level of packaging materials for fulfilling the requirements in legislation.
Typical legislation gives minimum requirements to a package. And you have to demonstrate minimal use of packaging material and still fulfil the minimum requirement. Earlier you have accepted a packaging design when the design passed the test. Now you also have to demonstrate that it is not possible to reduce further.