Unfortunately, Southern Italy and Naples, in particular, are considered the most crime-ridden regions of the country. Firstly, be prepared for attempts to scam you.
Waiters in trattorias, souvenir sellers, taxi drivers - all here consider it their duty to "poke" a foreigner, so be careful. Secondly, do not show your SLR or iPhone on the street and leave your gold jewellery at home as they might snatch it.
Carry your bag over your shoulder, don't put anything in your outside pockets and beware of young men on mopeds (they won't rob you, they might just run over your foot).
