Skip it.: Focus on posting an ad instead of replying to them, and know that there's a good chance it'll get flagged within 24 hours. There are a great number of folks on CL who are bitter, angry and/or frustrated with their lack of hooking up, and they'll automatically assume anyone who seems 'normal' is a prostitute.
I've spent many hours on these kinds of sites, talking to members, using the features, and generally trying to see if the sites offer what they say they do, while still trying to keep my (and your) privacy intact.
CL is a numbers game, and you'll have to respectfully answer as many ads as you can, showing exactly how you fit the criteria specified.
Oh, and if you're outside of what the ad wants?
During our two-week testing period, we found nine promising matches.
That’s not great when you consider the 70-plus results OKCupid served up for us, but it was better than any other site we looked at.