Rule 4-1-6 states: Hair devices made of a soft material or unadorned bobby pins and unadorned flat clips, no longer than 2 inches, may be worn. Hair adornment made of soft material and no more than 2 inches wide may be worn.
As such, given that the sequins on these headbands are very pliable (bendable), the interpretation is that these hair devices are legal and allowed under the NFHS rules for 2010.
This applies as well to headbands decorated with glitter.
Thanks, Mike