I know some people who train without insurance and it baffles me. I would encourage anyone to stop training until they are able to get some. As an anecdotal lesson, I had/have two herniated discs in my neck, went to the ER all night, had visits with three different specialists, four with my primary, was prescribed over 9 different medications in three months, was out of work for over a month and a half, and had physical therapy at least three days a week for a month. I hate my job as much as anyone can but I feel very lucky to have had the insurance and ability to take so much time off. I ended up paying around 300 (with copays, medication, etc.) whereas my bills would have been somewhere between 12 and 15 thousand without insurance.
Don't get me wrong, this doesn't apply only to jiu jitsu. I would be of the opinion people should refrain from a lot of physical activities if they don't have insurance. I've had friends who have had broken ankles, torn acl's, broken arms, etc., none of which happened during crazy rolling but were just the result of freak accidents. Even if you bump your lip while rolling and need stitches you're probably screwed.
I really can't stress it enough. It's a horrible feeling to be hunched over in excruciating pain while sitting in a hospital wondering if you'll need surgery or ever be able to train again, let alone facing financial ruin.