I'm retired now so no issues with leaving my bag in my office. However, when I did work in an office, I locked the door behind me. My bag is not so expensive, nothing like a Beltran, just an Osprey Kestrel 32. But the stuff inside is worth much much more, so it's in my shopping cart at the grocery store and between my feet or beside me whenever I go into a restaurant. If any place I'm going asks me to leave my bag behind or check it in somewhere, I just keep walking to somewhere else.