If there is a market for stuff there is one question, but I think what's most important is if there is a reason for you to have a vendor in fel?
I mean, aside allowing reds to shop freely at your vendor shop, I don't see what you could offer there that would make it worthwile. I think most people, probably reds included, would rather do their shopping in tram on one of their blues.
So basically all you'd get from that, would be less visit due to the people not willing to go the extra mile to get an item that they probably can get easily in a safer location.
Just my 2¢