In Australia and some other places, good-quality AC power plugs have "insulated pins". This means that there is a short length of insulation covering the base of the pins. Darren Yates writes that this has been legally required in Australia since 2005.
Insulated pins are a useful safety feature; they help prevent people from accidentally touching live pins and getting electrocuted.
In the US, AC power plugs (such as NEMA 1 and NEMA 5 plugs) seem to normally not have insulated pins. That is why Etotal IntelliHouse writes that they are not very safe.
Does any company manufacture NEMA 1 or NEMA 5 plugs with insulated pins?