Print-through is a consequence of tape being stored on reels with many layers of tape wound on top of each other. Any two adjacent layers can affect each other such that the magnetic field of one may partially magnetize the other. This can result in a noticeable pre- or post-echo added to the signal. Pre-echoes are more noticable because they precede the sound they echo whereas post-echoes are often masked by their source sound. 

This is the rationale behind storing reel to reel tape tail out. If print-through occurs, it will produce more of the less noticable post-echo this way.