Some ticks can find a nice place to rest on between hosts on a bed.
Especially if the tick was dropped from a host to the bed, the tick will lie in waiting until picked up by another host. A great way to prevent this is, after walking through tall grasses or under thickets of trees, have a partner search through your hair to see if a tick has latched on. Ticks also like areas around the ankles, waist and behind the ears.