"every mother knows her own child" but it has happened that babies have been switched in hospitals and mothers haven't found out until such times as a blood test has perhaps proven that the child was not biologically theirs.
Whether we like it or not, people find tradgedy entertaining - murder, programmes about child abuse, the corrie tram crash and all that involved, death and divorce ... and the list goes on.
And given that soap operas are supposed to portray peoples' lives, a sids storyline is not beyond the relms of that portrayal.
And yes the baby swap is completely stupid, but it's not supposed to be real, it's supposed to be entertainment, and whether we like it or not, about eleven million people find it entertaining, they're not going to lose millions of viewers over this; maybe a couple of hundred, but not enough to warrant them caring.