In Texas we have many people who drive without license or insurance. If they hit you they leave. The cost of everything is then yours to pay. Vehicle, medical, lost wages, passenger lawsuit, and whatever. I have heard of family and friends filing a law suit and telling the rider/driver "I don't want to do this but I have bills from the accident and medical cost and my lawyer says you are the only one we can find to sue." I don't let anyone ride in my truck or on my bike. I still carry lots of unisured motorist insurance.
TopSgt makes a lot of good points. There can be a lot of expenses that you may not think of until after you need the coverage and don't have it. Yes, your health insurance at work may cover your medical bills, but what if you are injured seriously enough that you cannot work and lose your job? Will you get to keep your health insurance if you are unemployed? What about lost wages, your deductible and copaayments on your health insurance, or other expenses you may have? What if you have to hire someone to take care of your household, which would not be covered by any health insurance, or you have to go into long-term care such as a nursing home? Health insurance typically doesn't cover that.
For full disclosure, I work as a claims adjuster and have handled injury and fatality auto and motorcycle claims for 25 years. There's not a week that passes that I don't see a claim here in Texas where the at-fault person has no insurance, or too little insurance. Like TopSgt said, many of them simply get out of the car and run away when they have an accident.
Yes, auto insurance is very expensive, and many people cannot afford any more than the minimum limits. Unfortunately, these are the same people who most need the higher uninsured motorist limits. I have to pay those same high rates; I don't receive any discount for working for the insurance company.
Another thing to consider: If your health insurance pays for medical bills incurred in a motor vehicle accident, they are going to expect to be reimbursed those expenses out of any liability settlement you might receive from an at-fault person's liability insurance. Their expenses could easily exceed the available limits if the at-fault person only carries the state minimum. Here in Texas that is 30/60/25. ($30K BI per person, $60K per accident, $25K property damage). If there are 3 people seriously injured, that $60K limit isn't going to go very far.
One recent claim I've seen in the past week has a $56,000.00 hospital bill for an overnight stay. That doesn't include any of the doctors' expenses; only the hospital. The at-fault person only has a 30/60 policy. Fortunately, the person carried uninsured motorist coverage, PIP, and health insurance to help with the bills, but none of those will be able to cover his lost income while being on disabilty except for the uninsured motorist coverage.
For older riders who may receive Medicare benefits, if they pay for any medical expenses from a motor vehicle accident they expect to be paid back. In fact, a recent Federal law requires insurance companies to report all injury claims to Medicare so they can determine if there's any funds they can recover. Failure to repay them can be a criminal offense for the person receiving the benefits.
I'll get off my soapbox now. Do I think uninsured/underinsured motorist coverage is important to carry? YES. Do I carry more than the minimum limits? ABSOLUTELY.
Just remember, there are more expenses when you are hurt in a MVA than just the medical bills.