As a crafter, I see two sides to this. Yes, people will buy things off other servers that are cheaper and as much as I could drive the price of an item up on one server I would find it hard to do on all of them. You buy out an item an hour or two there will be several for some expensive prices, within 12 hours most items are flooded out again. So there may be attempted abuse by players or mule money. On the other hand, I feel like it would open up the market to buy items that are hard to get on my server. I have checked other servers and sometimes they have rare items that no one uses and I can't find any for weeks up to months on my server. People I need to craft its what I do let me get my resources. FYI crafters don't always make a profit. Try making a sword that cost 2 million and people undercut and no one buys till it sells under a million. It happens more than you would like to think.