In most baby books, when there's advice about beginning crawlers, it usually says something like "Put a toy just out of baby's reach and s/he will crawl after it." Elizabeth doesn't seem to care if a toy is out of her reach. If I take something from her and put it out of her reach, or she throws something out of her reach, her reaction is to ignore it and move on to something else.
But she just cannot resist Bowden's toys. When we move them so she can't get them, that's when she takes off crawling, desperate to get her hands on his things. He's quite nonplussed by this turn of events and gives us these hurt looks that seem to say "Do you SEE what she's DOING?!" He knows he isn't allowed to touch her things and he doesn't, so he's having trouble understanding why she won't leave his things alone.
Maybe I just haven't found the right toys for her yet. I should try Petsmart.