There are plenty of tiny close-to-your-facec "cooties" on your pillow in a hotel, that is shared by many. They enjoy the free food in your open mouth, as you sleep:) I frequently bring my own new in-the-bag pillow when travelingb and leave it when I depart. I also leave my bags outside overnight in the winter cold when returning home from winter vacation and bring all the clothes inside for a wash in the morning. You cant prevent all foreign cooties, but you can limit the liklihood of transfering some.