His orders probably said zero tolerance for substances. Basis for violations are not always up to the PO. If the PO's supervisor read the reporting noted, he could've been violated as a result of the supervisor's directive. Knowing that he has been ordered to abstain and then divulging that he has is basis for violation. The PO does not have to issue a warining. He knew that he was not supposed to drink. He probably will be okay. Probably just a stern warning from the judge. Possibly a blood monitor on his ankle to detect any drinking. If he hasnot been ordered for treatment. He probably will have an amended order for an evaluation.

