Just be honest. I had to take a polygraph test for my job and that question was asked several times, several ways. I thought I would be disqualified, but I wasn't. I don't think they're concerned with what you've done in the past... they just want to make sure you're not coming to work under the influence or someone that would smuggle drugs into the facility. I was told when I took my test that there are gang members that are nurses that have never been arrested that apply for jail jobs so that there is a gang member "on the inside". That's a scary thought, working side by side with a gang member and not knowing it. The background check I went through was pretty disclosing and comprehensive. I'm sure those instances are few and far between, but it holds true, just as no matter how many locks you put on your doors, if some one wants to break in, they find a way.