Incorporating is not a cure-all, but it is a good idea. In most cases, a claim has to be made against the corporation, and in general only the assets of the corporation can be seized, not personal assets.
Anyone starting in business should also retain an attorney. While it sounds costly, a simple retainer can run around $100, and that usually includes an hour or so of advice. One of the thing you should consider having him draw up is a "bulletproof" acceptance of responsibility form. This is used when you take in a gun, and find it unsafe. The form has to be signed by the customer to get the gun back and essentially says you warned him of the danger, absolves you of blame for any problem, and accepts any reponsibility for damages.
One of the big problems in a hobby business is that too many people treat it like a hobby and not like a business. They work long hours for peanuts, buy for their own collections and not to sell to make money, etc. Some concentrate so much on things like Federal licenses and laws that they forget common business laws, like business income tax, employee laws, zoning laws, bookkeeping requirements, etc. Maybe Abe Lincoln kept all his papers in his hat, but today he would need a much taller hat, with room for an accountant.
While it is hard to believe today, most accountants and lawyers really are honest and competent.
Jim