There's better and less expensive coverage, than the NRA policy.
The NRA policy provides reimbursement for legal expensives if you are aquitted or charges are dropped. You're still going to have to pay out of pocket, and try to get your money back later.
I never could get a straight answer from them, when I asked if they provided coverage if I was sued for wrongful death.
You can get better coverage from your homowners or renters policy, talk to your insurance agent. You want coverage that's similar to what a children's daycare service would carry.....Coverage for certain criminal acts. The catch is that you won't get to choose your lawyer, your insurance provider will.
Talk to your lawyer before you go and buy liability insurance. Depending on you financial situation you may not need it. If your judgment proof, on the verge of bankruptcy from your criminal defense, etc, and you don't have insurance your probably not going to get sued, there's nothing for the other lawyer to win. If you do get sued (Bernie Goetz or OJ) you don't have that much to lose.
If you have assets to protect make sure they a properly insured.