I think technically there's some statistical correction you apply to the voxels to avoid this. But yea...most hypotheses from fMRI are considered hypotheses until there's some other modality, i.e. electrical recordings, etc that confirm it.

i.e. the well regarded studies, i.e. Kanwisher and the visual processing areas, have follow up studies on primates and surgical volunteers w/ actual electrical activity correlating w/ visual stimuli etc