You do know that they're not secured at all? They're free to come and go as they please, they're even providing free buses to neighbouring towns.Their chances of getting into this country are about 1/20 and most of them will be sent back; or get a free flight to Rwanda where they can explore the Heart of Africa. Perhaps they'd enjoy a guided tour of the airbase during their stay.
Those other 19 of 20 will be told to wait there for their flight back to wherever they came from. How many do you think are really likely to just wait around there? They'll disperse into the population, working cash-in-hand, or get money by whatever other means they can.
This is by design, the government wants them to go missing.