Does cheaper car insurance come with hidden risks?

Not necessarily. If the insurance cost to you as the driver is low, it is likely due to some factor in your control such as driving record, deductibles, the car you drive, your credit history and more. Further, there are state minimums as to what you need to have for coverage. In Kansas, specifically, drivers need $25,000 of bodily injury per person, $50,000 of bodily injury per accident, $25,000 property damage liability per accident, $25,000 uninsured/underinsured motorist coverage per person, $50,000 uninsured/underinsured motorist coverage per accident, and personal injury protection including $4,500 in medical expenses.
So, assuming the driver is following the rules, they likely have some coverage. However, state minimums are probably not going to go far. These types of policies are not comprehensive and are minimum coverage amounts and will often be the cheapest. However, in severe accidents, these amounts can easily add up, particularly the bodily injury and property damage. Even in an accident with just one other car and you're at fault, if the vehicle of the other driver is brand new, the property damage will likely be exhausted with just the other driver's car. In terms of quality of service, that simply requires the driver to shop policies and learn about the companies offering policies to them.