Asking a random stranger to watch your stuff is safer than leaving your stuff unattended. Firstly, there are risks other than theft. Someone might throw your stuff out in an effort to keep the place safe and clean. Secondly, though thieves do not wear signs around their necks reading "thief," your intuition might help you find someone trustworthy. Thirdly, if you do have terrible luck and intuition and you trust a thief, if you find your stuff missing, you know who took it.