Is it permissible for two witnesses to testify about an accounting session between two parties if the parties stipulated that the witnesses should not retain any record against them?

Primary text

If two witnesses attend an accounting session between two individuals and the parties stipulate that the witnesses must not retain anything against them, the witnesses are still permitted to testify regarding what they heard. The stipulation does not invalidate their testimony because a witness is permitted to testify regarding what they have heard or learned, and that knowledge has already been acquired, regardless of whether they were explicitly instructed to be witnesses. Similarly, witnesses may testify regarding contracts they witnessed and felonies they observed without needing explicit instruction (Ishhad). This position is held by Ibn Sirin, Malik, Al-Thawri, and Al-Shafi'i.