The jeans rack is always my first stop whenever I go thrifting. I have heard of the Evisu brand before, but have never purchased a pair of their jeans. I actually used my cell phone to research the completed sales on eBay and to check the authenticity on the eBay Reviews and Guide section.
There are a lot of Evisu FAKES out there. I actually came across 3 fake pairs late last week. Since I am inexperienced when it comes to the Evisu brand, I would of passed up on them without my cell phone to make sure I was buying the real deal.
The easiest way to determine if you have a fake item while at the store is to run a google search with the words fake and the designer name you are looking at. The eBay guides section which it a great resource is usually at the top of the search results.