Why is having an application (or agent) on the device important?
In order to detect jailbroken devices — and thus keep corporate data secure — devices must have an agent installed, and the agent must be part of the registration process to ensure that the agent and device are identified with a specific enterprise user. The agent also can check the device and analyze its posture, monitoring for compliance with corporate policies. Without an agent, the device could be compliant during the initial registration process but non-compliant later. Based on the current state of the device, the agent can block the device from corporate resources and send alerts.