According to the Citrix Virtual Apps and Desktops 7 2308 documentation1, the default printing behavior when no printing policy is configured is to auto-create all client printers. This means that the system automatically creates printers in the user session that correspond to the printers defined on the user device. This option provides users with access to the same printers in a session as they have on their user devices.
1: Printing policies and preferences | Citrix Virtual Apps and Desktops 7 2308