Look at it this way. Is it worth the extra time and effort to avoid spending a few dollars, and trade in that time/money for a nice looooong talk/scolding with Disney's Security personnel if the tickets are found to be fake? Or better yet, maxed out on the usage?
It's better to save yourself the effort and potential stress by just buying a legit ticket from a legit source. If you don't, it's only yourself you'll have to be kicking later. Besides, didn't someone just try this and end up getting busted at the front gate? I can't remember if that was on this board or another, but it happens, and can be quite embarassing as it turns out.