Normally, it is not wise to carrry your passport with you, however in dangerous countries, the police and military are always checking your visa.
A few days ago I entered a dangerous country, Cote d'Ivoire, by the time I traveled from the Elbow / Noe border to Grand Bass am, the military or police had stopped the car 15 times.
While walking around in Grand Bass am, i realized was not in the same country as before the Election. Bugaboo the president refused to step down, and now the country is in the middle of a small civil war.
Normally, I never seldom carry my passport with me, maybe a copy, however in an extreme corrupt and dangerous country, I will carry for safety.
Normal Countries do not carry your passport.
Extreme Adventure Countries, at war, under seige, you need to carry your passport.
Andy Graham in Ivory Coast February 2011