Bound to Server
Clearly you can’t have players going off and spying for the other side in WvW or choosing their side based on how good the servers are, so it makes sense having that account restricted. As to other stuff – there will be a guesting feature, but it isn’t implemented yet.
One thing I would like to do is to be able to represent both an EU and a US server, since I am an EU member of an international guild with players all over the world. That wouldn’t be a problem for WvW since the EU & US leagues are separate.