It’s not a big concern as yet but my little girl has a growing interest in scribbling on desks, tables and our poor TV screen with her crayons!  I’m glad she has stayed away from doors and walls so far.  Otherwise, poor mama will be scrubbing and swiping the walls clean every day.  It does help though that she has her own play desk (smaller than classroom desks) and an easel board where she does most of her doodle art.