From Kolar's book - pages 228-229:
"It would take a year before the black and red Essentials brand
jacket Patsy was photographed wearing was finally delivered to
them. It was frustrating. The clothing articles seemed to trickle
into their office a piece or two at a time. In one instance, a sweater
that Patsy was said to be wearing under the jacket was
delivered that looked like it had just come off the shelf of a retail
clothing store. The fold marks were crisp and clearly present,
suggesting it had never been worn.
Trujillo advised me that lab technicians had identified eight
different types of fibers on the sticky side of the duct tape used to
cover JonBenéts mouth. They included red acrylic, gray acrylic,
and red polyester fibers that were subsequently determined by
laboratory examination to be microscopically and chemically
consistent to each other, as well as to fibers taken from Patsy
Ramseys Essentials jacket.
Further, fibers from this jacket were also matched to trace
fibers collected from the wrist ligature, neck ligature, and
vacuumed evidence from the paint tray and Wine Cellar floor.
Some intruder theorists thought that the transfer of Patsys
jacket fibers to the duct tape may have taken place after John had
removed it from JonBenéts face, and placed it on the white
blanket in the cellar. They believed it possible that prior contact
taking place between the blanket and jacket could account for the
transfer of these fibers to the tape.
Lab technicians had conducted experiments with the same
brand of duct tape, by attempting to lift trace fibers from the
blanket recovered in the Wine Cellar. Direct contact was made in
different quadrants of the blanket. There was some minimal
transfer of jacket fibers made to the tape during this exercise, but
Trujillo told me lab technicians didnt think that this type of
transfer accounted for the number of jacket fibers that had been
found on the sticky side of the tape. It was thought that direct
contact between the jacket and tape was more likely the reason for
the quantity of fibers found on this piece of evidence.
BPD investigators looked to the other jacket fibers found in
the Wine Cellar, in the paint tray, and on the cord used to
bind JonBenét as physical evidence that linked Patsy with the
probable location of her daughters death the basement hallway
and Wine Cellar.
The paint tray was reported to have been moved to the
basement about a month prior to the kidnapping, and investigators
doubted that Patsy would have been working on art projects
while wearing the dress jacket. The collection of jacket fibers from
all of these different locations raised strong suspicions about her
involvement in the crime.
Investigators also learned that fibers collected from the
interior lining of the Essentials jacket did not match control samples
from the sweater that had been provided to police by Ramsey
attorneys. Investigators thought that this suggested she had been
wearing some other article of clothing beneath the jacket."
Sounds as if she (PR) might have torn the tape and stuck it to her jacket while she finished doing something else. I've done this before with duct tape. Tear a piece off and stick it to my shirt so it's ready when I want to place it.