When that sort of situation arose for me, it seemed mostly just that companies I wanted to work with weren't really set up to handle individual freelancers. They weren't trying to scam me or let their buddies skim off the top. So, I made an S-Corp. Haven't had a problem since.
Also makes it easier to do stuff like get project insurance, which some clients have also required. It's not expensive or time-consuming, you just have to jump through the hoops the bureaucracy wants you to jump through sometimes. And if that makes you uncomfortable, then you don't have to go after or take those kinds of gigs.