Is Wi-Fi Direct secure, and how can I make it more secure?

By default, the Wi-Fi Direct setting is in 'Automatic' mode without an administrator password, which allows anyone in wireless range to connect and access all printer functions and settings. If higher security levels are desired, HP recommends changing the Wi-Fi Direct Connection Method from 'Automatic' to 'Manual' and establishing an administrator password. This product is designed for use in open environments such as homes. (Page 2)