As a resident, you are also held to the standard of an EM attending. You can't sit up there on the witness stand and say "well, I wasn't the attending". Your name is on the chart. If you **** up, you're getting sued. Hell, if you blink funny, you're likely to get sued. That being said, you'll be the only person on the lawsuit if you're moonlighting.
Moonlighting increases your risk of lawsuits as an absolute only because you see more patients. On average, EM physicians are sued once for every X patients (I can't remember or find the exact number). If you moonlight, you see more. It doesn't increase your relative risk unless you're actively doing something wrong.
Looking up at the poll, I laughed at the board certification. I'm guessing the implication was board eligible.