Why was there no 'skinship' between Yoon Si Yoon and Kim Sae Ron in 'Witch Exemplar'?

In a July 23 interview with etoday, Kim Sae Ron talked about her recent drama 'Witch Exemplar,' particularly her 'skinship' (or lack thereof) with co-star Yoon Si Yoon. 

The actress began, "I think I was able to finish 'Witch Exemplar' without any troubles thanks to Yoon Si Yoon's considerate nature." 

Kim Sae Ron continued, "When we first started 'Witch Exemplar,' there were many people who were worried about whether I'd be able to create a good chemistry with Yoon Si Yoon because of our 14-year age gap. But Yoon Si Yoon took care to make me feel comfortable so that I wouldn't really feel the age gap [between us]. So I didn't really feel that there was a big difference in our age." 

Kim Sae Ron then talked about how there were no kiss or physical contact scenes in the drama, saying, "It's not that there were none because of my age. After the director, Yoon Si Yoon, and I debated and though it over, we decided to showcase a 'hidden kind of romance' so that's why there were no heavy physical contact scenes."