Ill. Admin. Code tit. 56, § 300.820
A financial loss suffered by an employer due to damage to his/her property or to that of a customer or client shall not be deducted from an employee's pay unless the employee's expressed written consent is given freely at the time the deduction is made.
(Source: Added at 16 Ill. Reg. 13828, effective September 1, 1992)