I do not understand how... I lack the executive function to parse how others are working around it, though my partner is trying. Are you using Launchbuddy? If so, just uncheck the "Use -autologin" box on the Account Manager window, then hit Launch Guild Wars 2 at the bottom of the screen as many times as it takes to open the number of instances you want. You'll have to log into each of them individually, but they'll all run.