Why you are flamign people on the Interweb, what have I doed to deserve this?
Let me try again:
I believe Blizzard is not denying dupes, because they said so. Blizzard has a"Security by obscurity" philosophy to not talk about details, but they do acknowledge that exploits happen.
Examples:
From Reddit (and I saw a similar post on MMOC with Screenshot:
"GM opened a chat window with me and told me they were going to remove the rest cause they came from a illicit source. They removed all the remaining queen's garnets (including some of my own [im a JC]) and paid me 2k per each of the ones they removed "
http://eu.battle.net/wow/en/forum/to...3877?page=1#11
http://us.battle.net/wow/en/forum/to...2357?page=2#33
Blizzard does lie, a lot:
http://eu.battle.net/wow/en/forum/topic/14821402417
But this has more to do with overpromising or changing minds and is not active deception to do their bidding.
Now your turn. Show us what made you believe they deny duping.
OT again, in case this got lost:
Back in 2014 one Chinese Exploiter whom I purchased several Spectral Tigers from abruptly told me "US only, no more EU" and I guess around 6.1 everone's stockpiles ran dry. This should answer OP's question regarding the UE/EU price descrepancy.