It might not be a felony but it is definately a crime. Punishable by a fine and perhaps jail time if it is a repeat offense or in conjunction with other criminal charges.
Whether or not it voids the policy I wouldn't know. I suspect it depends on the insurance company. Even if it doesn't void the policy I'm sure you could count on there being a hefty increase in the policy's cost.
In any case, I wouldn't be concerned about how much law breaking you can "get away with". You'll end up paying for it either in the short term. long term, or both. In the end it will cost you.
Say you get in an accident and cause $10K in damages. Without policy coverage, you are liable from the start. With a policy, the insurance company foots the bill. But rest assured they will get the money back one way or another.
Not to mention getting a "blot" on your record. Forget about getting any credit.