Some airlines also look at your civil record, ie lawsuits. They want know if you make a habit of suing you employers, and they are also interested to see if you maybe got sued for something you did that that was unethical or criminal in nature...just because you didn't get convicted or indicted, doesn't mean you're innocent.

Also they will probably check references with past non-aviation employers as well. So when you're finally ready to quit driving for Dominoes, don't be like Judge Reinhold in Fast Times...