You could equally say that Buses are more of a target - stop one vehicle and you get loads of people to fleece.
If the road is sealed you could just follow the bus, if the road is unsealed, forget it unless you like eating dust. Best of both worlds then.
When I was there in 2009 there was an alert out for hijackings and so forth, it is situation normal in BK, though the government was trying to stomp it out. The latest unrest has probably made it easier.
My advice would be to avoid the common tourist routes (ie: don't cross from Mopti/Dogon in Mali) and talk to the police at each checkpoint for advice. They are quite professional in BF, even with name tags! Then again, who has actually been robbed? Tourists or local mini buses etc??
Most importent of all is don't drive too early or too late in the day. Many of these 'bandits' are just pissed off locals/farmers who are starving, though you'll often hear they are Nigerians as everything is blamed on them.
The area around Banfora and Bobo is nice and the border crossing near Banfora/Bobo into Ghana and down to Wa and the Mole National Park is quite fun.
Good luck, keep your wits about you and you'll be fine unless you have luck like mine