I agree. There are a lot of vendors that have items that are 'not' rare and they are trying to sell them.. the stealing bugged items are my pet peeve as of late like the empty vials, gold bread, dark red bloodspawn, etc. I'm not saying they aren't worth something for deco like red birds, green arrows, blue apples etc are, but many are trying to sell them as true rares and for millions either from greed or ignorance of their origin.
To be honest though, this isn't a issue of other folks coming here and doing it. This happens to every shard who hosts a festival. I'm seeing it happen on vendors that are owned by pacific players as well. Its sad, but its gonna happen. The only thing we can do is try and educate the population so they know the true origin of an item before making a purchase.
Educate yourself on the origin of the item you are wanting to buy. As much as it kills me to say this, don't always trust the description on any item. Always double check on the rares forum or ask an experienced merchant first.
Please be safe folks.