In Tokyo it seems the only things that get stolen are bicycles (or their parts!) or umbrellas! I recall a news reporter leaving a camera at Shibuya crossing (a very busy interchange) and it remained there overnight and beyond, noone picked it up. You can "reserve" your table in a cafe or fast-food outlet by leaving your designer purse/wallet on it - it will still be there when you get back to your seat and noone will complain!