The defense to this is multiple LLCs and licensing schemes. Just like the troll, don't hold any assets in the vulnerable LLC. If Walmart sells a bootleg shirt the IP holder can't sue the company that cleans the parking lot.
Not really. It's worth it and very effective for business with significant liability risks. The corporate structure of a basic gym will have like 6 entities if it's done properly.
Probably ineffective too, as some part of your firm must hold the assets, and that's the part that gets sued