When you phone the 24 hour hotline, the dispatcher passes the information (reported violation, reporter's contact) to the regional office that is closest to the location where the violation has taken place. The officers at the office, if they are not on the field or doing important paper work, will attend the violation. Many times it's not unusual for the officers to phone back to retrieve more information.
The reality is that not every reported violation can be attended. The officers do their best to cover whatever they can. If the violations are taking place at one specific location repeatedly, they officers will most likely put that on top of their list. Anytime a thread posted here regarding repetitive violations, I usually email them to the main officer in charge in that area.
They always welcome feedbacks, encouragement and assistance, so phone in any violations you observe.