They leave out more wood than a camper would even think to take because they only need one bundle every day or two. The sort of person who would need to steal a whole season's worth of wood is less likely to have the means to transport it all, and if they're so desperate that they'd go to the trouble then the Christian thing to do would be to let them have it.

Gillette razors on the other hand, are expensive to stock for their size, and easy to steal because of their size.