Denominations that don't practice infant baptism would allow those adults to be baptized because they don't regard the first one as authentic.
It's true that denominations that practice infant baptism usually don't allow adults who were baptized as infants to be re-baptized, because they consider the person to be already baptized, so there's no need.
But even in cases where denominations try diligently to avoid the case where they're conferring baptism on someone who may have already been baptized (as in the case of the Catholic church and conditional baptism), there are no penalties for baptizing someone who was already baptized. It's just sort of a pointless thing, unless you reject the idea that infant baptism is legitimate, in which case why belong to a denomination that practices infant baptism?
Maybe there were penalties in the past that I'm not aware of, so I'd love to learn more about the executions.