Walmart offers the ozark trail 25 liter Hiker daypack here
It has 2274 reviews. If 1/10 of buyers post a review then that would imply about 23000 such daypack buyers. Stiff but perhaps not insurmountable find odds if the police slog through the entire list. However that would be if the daypack were only offered in the USA. There are also Walmart stores in Mexico…
I do not have such a daypack available for examination by me right now. However, it seems to me that there are two movable strap reflectors, one on each strap. Each of These have been positioned to the upper part of each strap. One would do this mainly to increase visibility by oncoming automobiles when wearing the day pack at night while walking or riding a bicycle.
So, there is a chance that the intruder repurposed the day pack from his normal everyday use to the kidnapping.
The reflective tapes are evidently very bright in the glare of piping light. This imho increases the chance that someone will recognize the guy.
Also the daypack did not seem to have any scuff marks on the back fabric as a normal daypack would have with a modicum of normal use. So the police might benefit from processing the Walmart customer purchase list in reverse chronological order (starting with the most recent and working backwards).