Tosfos in Pesachim 2a discuss why Yosef's brothers were not allowed to go by night. Tosfos say that the reason was because they were not familiar with the territory, and they could have fallen in potholes, but since they were ten they need not have been scared of 'mazikim'. What is the din today? Does a person going alone in his own city which he knows well have to be scared of mazikim? Does this only apply to a talmid chochom, perhaps? Or maybe mazikim don't exist today?