Musannaf Ibn Abi Shayba 13:1504

Abu Bakr narrated to us, he said: Abd al-Wahhab al-Thaqafi narrated to us, from Khalid, from Abu Qilabah: Regarding the *mudarib* (the manager of a profit-sharing partnership), if they stipulate to him that he shall not cross [a certain boundary or travel to a certain place], and he crosses it, then he is a guarantor.