Smit believes the crime scene photos show disturbance in the window well. I agree. He also believes that trace material from the window well, trace that was found in the small room a distance away, and around some corners from the broken window indicate that those items were probably moved by transference on the intruder's clothing and shoes.
When Smit and others experimented at the house, and entered the basement window to demonstrate it could easily be done, disturbance was also created in the window well.
In addition, Smit said that some of the packing peanuts clung to his clothing by static electricity when he came through the window, and that's how he theorizes the packing peanut from the window well ended up in the windowless room where JonBenét's body was found: it came in with the intruder who killed her.
"Proof" is usually in the interpretation of potential evidence, and I think "ironic" probably is also an interpretation. Smit's forensic interpretations have been invaluable in his long & successful career as a law enforcement detective.