Kids don't even know or understand what they're doing half the time...and it's not on purpose, they're just kids. My Dad bought a huge wooden big screen TV back in the late 80's and if you were around then, you know how expensive those were. The screen was plastic and it had lines in it, it thought it was cool and started scratching it with my finger like a record, it sounded cool....I had NO idea I was leaving permanent marks in the screen because when the tv was ON, you couldn't really see it, but when off, it was ugly.
My Dad threatened to set me on fire and bury me in the backyard like my older brother...I told him I never had an older brother...he said that you KNEW of....really freaked me out for about 5 minutes till I realized he was joking.
That being said I can imagine kids not knowing any better taking markers or colored pencils to your cabinet like a giant coloring book and not even realizing what they're doing.