They don't have to be deflected - at least not for the interesting part of the effect.
If charged particles are deflected, they emit electromagnetic waves. To get visible light, you need very high-energetic particles and special magnetic fields.
so I can get an electron to emit light even if its not in a B or E field.
I don't believe so. I think MFB was referring to the fact that in the Aharonov-Bohm experiment the charged particles don't have to be deflected in order for the interference to be shifted. To get a charged particle to emit light you need to accelerate it somehow, such as with an electric or magnetic field. If there is no acceleration then there is no light emission.