Kissing baby/Touching baby with dirty hands

http://www.fox46charlotte.com/news/268688871-story

This is a sad story of a perfectly healthy newborn who contracted a disease from being kissed by someone with a cold sore.

I am dreading having to deal with my in-laws being around my baby because they are trashy/dirty people.

What has been your experience with people wanting to kiss/touch your baby with dirty hands?