When these items were placed in the 1e DMG, a book which was not meant for players to read (with the author even going to the point that any player perusing the tome was worthy of a "less than honorable death", lol), players had no clue that this thing could happen. Identify was not a spell your Magic-User was guaranteed to have, nor use, since it cost 100 gp to cast, and even then, it had a chance to identify items, and the spell temporarily drained you of 8 points of Constitution!
So yes, accidentally placing a bag of holding inside a portable hole was not only a strong possibility, but the kind of "gotcha" that early D&D was infamous for- the survivors would know better, presumably.