Working Dogs
An interesting article in The New York Times on explosives- and drug- detecting.
All in all, it's a pretty good article and covers well the critically important issues that dogs doing scent work can have.
I do have to comment on this, though:
Creatures of habit, dogs also can become stuck in their ways. For example, a dog might become fixated on a particular object or smell, Dr. Myers said, citing a police dog in Alabama that began alerting its handlers to Ziploc bags because the police stored drug training samples in them.
This is not being a 'creature of habit' or 'fixating on a particular object.' This is insufficiently explaining what you wanted. The dog was correctly indicating Ziploc bags. It was the handler's mistake for not understanding what the dog was learning. It's like playing those games--which object am I thinking of--the dog keeps picking Ziploc bags and keeps getting rewarded. Gee, what's it supposed to think?
Dogs know how to scent (compared to them, we have No Idea). They're incredibly good at it. But they only know what we want them to scent and to detect by scenting by what we teach them. If we're not clear, if we don't understand what they're telling us, if things happen quickly and both handler and dog get confused, there will be false results.
I agree with the article that false reports of explosives are better than missing real explosives. Increased accuracy and skill are even better.