> I'm wondering why there isn't anything done for scent detection ... it would limit the need for drug sniffing dogs

If police departments believe that they get the resources they want based on the Clever Hans Effect, what would be their incentive to use a more accurate mechanism for sniffing out drugs?

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3078300/

http://articles.chicagotribune.com/2011-01-06/news/ct-met-ca...

https://en.wikipedia.org/wiki/John_Preston_(dog_handler)