IBB / BSB

[TexDoc]

Can an illegal block in the back be "upgraded" to a blind side block?

[TXMike]

This would be true unless the player blocked was a mother.  We know that all Mom's have eyes in the back of their head!!    (Rights for use of that line were stolen from TxSkyBolt)   

[Kalle]

If we are talking about the "normal" varieties of IBB and BSB, I think an IBB isn't really a BSB. A push on the back is much less dangerous than a body check from the side, as then you have momentums colliding and creating extra force. Of course by definition a block in the back can be an illegal BSB, but I think those cases are rare.

[mccormicw]

Since the criteria for blind side block is "an open field block against an opponent that is initiated from outside the opponent's field of vision....", I would say that location of the block (Back, side or front) is not a factor.  Only factor is that it is initiated from outside the opponent's field of vision.  If the contact is forcible and outside the opponent's vision, it is illegal.  If the block is in the back on not forcible, go with IBB.