Answer the question in 5 sentences based on the following scenario.

Frederick, a man in his 30's, signs a plea offer to a possession of drug paraphernalia charge and is sentenced to probation for 12 months in his county. He has been on probation for 9 months. One of his requirements while on probation is a curfew from 6pm-9pm. You decide to do a quick drive by and notice his car is not in the driveway and Frederick is not inside. It is 9pm. After getting in touch with the offender, you are told that he had to go check on his mother at her house. As his probation officer would you excuse this one incident or violate him for failing to adhere to his curfew rule?