The Be'er Hagolah 5 attributes this advice to a Meimra of Rav.
Questions for contemplation:
A. Had this SAME harchaqah been issued by a Rishon such as Rashi or Rambam or Tosafot, would we perceive it any differently?
B. Or what if an Acharon such as the M'chabeir or the Rema or the Mishnah Brurah had been the first to issue this ruling - would it really matter?
Finally, what if we figured this out on our own? Would this have been an over-the-top humra, or just plain common sense?