Questione giuridica chiave
Whether a debtor may validly waive set-off in advance by promise to pay cash.
Decisione estratta
Yes. A debtor may waive set-off in advance under Art. 126 CO, and the waiver is a contract formed by mutual assent, express or implied.
Motivazione estratta
A cash-payment promise made in knowledge of the counterclaim may, depending on the circumstances, be interpreted under the general rules of construction as an implied expression of intent to waive set-off. If the creditor may in good faith understand the promise as such a waiver, the waiver is effective even if the debtor did not subjectively intend it. The creditor need not expressly declare that it treats the statement as a waiver; tacit acceptance by conduct or silence can suffice when no express acceptance is to be expected.