Reminds me if what happened to a pal's wife last month. She'd just withdrawn some cash from the local Barclay's bank branch (not in Nbi) when, out in the streets, she was accosted by armed young men who calmly demanded cash from her and even seemed to know the exact amount she had withdrawn. She gave them the money and off they went, melting in the crowd. They didn't even want her rather expensive phone.
She took some time to recover from the shock of it all. Later, as she boarded a mat home, a mathree conductor she knew asked her 'aih, mathe, nini hii iko kwa nguo yako mgongo? Wacha nikutoe'. Turns out someone at the bank queue, she couldn't tell who, had placed a sticker on her back and this is what the thugs used to identify her once out on the streets. Similar tactics gave been reported at Coop where victims later found marks on their clothes that ostensibly served to mark them out.
Life is like playing a violin solo in public and learning the instrument as one goes on.