I like to get people into cycling, so even if I've had a bad experience with loaning my stuff to people I usually wouldn't hesitate to lend my bike to someone else. Last night I loaned my mountain bike to a friend (he got hit by a car and is waiting for a new front wheel for his bike) to ride with me to a show; he stood my bike upside down and walked away from it disregarding my warnings about bike theft, so I know that I will not be loaning this friend any of my belongings again.
But I'm going on a ride tomorrow, and I'm loaning another friend the same bike because he's someone that I do trust to take good care of my stuff and I'll be happy to have his company.