I don't think the color of the hair ties is nearly as important as the big brown butterfly hair clip she was wearing when found. I think it's long since been established what her hairstyle was at the White's since LE had the photos from the White's party quite some time ago. They use some of them to show to PR and JR in the 8/00 interviews to refresh their memories as to what clothing they wore to the White's. None of the photos at the White's have been made public.
This is an autopsy photo that shows the big butterfly clip that JBR was found to be wearing in her hair...
http://www.forumsforjustice.org/forums/attachment.php?attachmentid=2017&stc=1
(it's not gross, just a close-up of the hair showing the clip and part of one hand)
Seeing as the syle and ornaments are different from Patsy's testimony about how JBR's hair was normally styled when she was put to bed, I just see the hairstyle as ulitarian (get it out of the way to put the garrot on) as well as additional staging (style the hair differently than how it was normally styled).
If I recall correctly, the housekeeper said that JBR's hair ties were kept in a basket in her room. In one of the photos of JBR's room it appears that a scrunchie hair tie is around one of the bedposts and something else that looks like it may be a hair tie bellow it on the bedpost (some pink ribbon type thing)...
http://www.acandyrose.com/002jonbenetbed.jpg
I would imagine it would be known by LE whether or not the things Patsy believes to be the cloth bands used to make the potholders are hair ties or not as these cloth bands are all uniform (although vary in color), far too large to be used normally as hair ties, and hair ties would vary in size, shape and what they're made of.
What I do find interesting about the plastic potholder making device, is whether or not the prongs may have been the cause of the "stun gun" marks on JBR. I'd be curious to know what the size of the gap was between the two corner prongs, and I can see if one used it to strike someone if held at a certain angle, it may be that only those two corner prongs would connect with the skin and leave a mark... could be that's why LE took a photo of it...
http://www.acandyrose.com/000dresser.jpg