I am only aware of lawsuits involving manufacturers. Generally they are the more attractive targets for torts due to a perception of deeper pockets and an inclination to settle in order to protect the firm's reputation.

I remember being peripherally involved in a case where a fellow got drunk and decided (despite zero piloting experience) that he wanted to fly his friend's single seat ultralight. He ended up dead. The lawyer for his widow was mostly interested in whether there might be some defect in the aircraft that made it dangerous for non-pilots to fly. (I'm not making this up).

Of course that doesn't mean a lawsuit against an individual hasn't happened - or can't happen. If there is injury or property damage, expect that someone will be asked to pay. The deeper your pockets the more likely that someone will be you.

I recommend carrying insurance if you have any assets you care about keeping.

Andy
9B