Last night, Mythbusters had a world class blood hound on the show. They tried to fool the hound using several tactics:

The 'suspect'took a shower and the hound found him.

The 'suspect'put pepper on their scent trail and the hound found him.

The 'suspect'used cologne and coffee as coverscents onhimself and the hound found him.

The 'suspect'walked through a populated downtown and the hound found him - with some difficulty.

This was their opportunity to try Carbon Clothing! ...but they didn't. It does reduce my confidence in the concept of cover scents.