An unexpected result

So, a large majority of my ethics students at Rhode Island College said they thought there was nothing wrong with prostitution if it's voluntary.  Admittedly, I elicited this result in a potentially suspect way; when nobody said anything about why prostitution would be different from any other job, I told them to raise their hands if they thought it wasn't different, saying I'd call on someone who didn't have their hand raised.  It is thus possible that some falsified their responses to avoid being called on (though I'd have thought some might also have lied to avoid admitting to endorsing prostitution).