Some tie off with a string, while others have elastic in the band to keep the snood on ones head.
Snoods are convenient.
Unfortunately, the snoods you usually see sold at renaissance faires aren't themselves authentic. Crochet wasn't invented until the 17th century. Although there aren't many images of Hairnets and bag hairdresses before 1550, there are some to be found. This bag-coif has a silhouette similar to the wired coif of the time, but has a gathered bag at the back covering the girl's head. The fabric of the bag could match the dress, as does the bag to the left.