If a party tolerates a breach of contract, such as delays. B delivery, a judge might consider that he has waived his right to demand delivery without notice. The purpose of the non-waiver clauses is to provide that a party`s failure to respond to a violation does not waive its right to react to another. However, the parties cannot choose a foreign law for convenience to escape mandatory provisions of the law that would otherwise have naturally been applicable. In such cases, a court may apply these mandatory provisions regardless of the choice clause of the law. In addition, a court may postpone the lex contractus if the results of their action were clearly contrary to the public order of the forum. If the parties do not provide for an express clause of choice of the law, the courts can also: when a court that rules on the merits of a case, it can, when deciding on a dispute, sovereignly settle all opaque and ambiguous contractual conditions. However, judges cannot make clear and precise provisions. However, failure to interpret a contractual clause that could affect the outcome of a proceeding because of its ambiguity would amount to a miscarriage of justice. The law often changes or is sometimes obscure (it is not uncommon for court decisions to conflict).

Moreover, it is not uncommon for a party attempting to escape liability to assert that a contractual clause (or the entire contract) is undauctivityful. In order to prevent a provision that may be null and certain from nullity, the entire agreement should be nullified, a dissociation clause should be added. This deterrence clause provides that a provision, if struck down, does not affect the validity of the other parts of the agreement that remain fully in force. It may also require the parties to negotiate in good faith an existing replacement provision reflecting their original intent. Finally, the parties must, in principle, respect not only the explicit provisions of their contract, but also all the conditions associated with them, through capital, customs duties or law. As a result, judges may discover obligations that have not been explicitly included in the contract, such as the obligation to guarantee the safety of passengers in a transport service provision agreement.