Perhaps it's because you're ticketing the vehicle's registered owner, but not necessarily the driver.
That's not entirely true, it depends on your insurance. It's an offence to drive a car without insurance, and an offence to allow someone who is uninsured to drive your car. Some insurance policies do not extend the insurance you took out to driving other peoples cars. However, some fully comprehensive policies do have third party insurance while you are driving someone else's car with their permission. In that case it's fully legal to drive.