My interpretation of all rules I have researched specifically state the a player is responsible for protecting their hand, and if they FAIL to do so, the player is due no redress.
I agree.
I maintain that the player did, in fact, protect his cards, by placing a protector (or card cap, according to WSOP rules) on the cards, and therefore IS due redress.
I don't think this statement, which is essentially the converse of the statement above, is necessarily true or follows conventional thinking on the subject.
Just because a player takes
some act of 'protecting' his cards does not mean he is entitled to relief if his cards end up in the muck.
The real question is whether the placement of a chip or some other object on cards should be considered an action that should be sufficient to discharge the player's duty to protect his own hand. While there may have been some disagreement on this issue in the past, I believe the current widely-held view is that cards that unintentionally find their way into the muck, necessarily, must not have been
adequately protected -- otherwise they would not be in the muck.
Unless the dealer maliciously ripped cards right out of a player's hands, ultimately the player is wholly responsible to ensure that his cards do not end up in the muck unless he intends that the cards be there. Let's face it: no one but the player has final physical control over where cards end up after those cards are pitched to him by the dealer. Therefore, the player really needs to bear the final responsibility for the hand, unfortunately, even if dealer error is involved and the hand gets mucked.
This usually means that players may need to keep a hand on their cards to protect them, if a chip alone might not be enough to adequately protect the cards -- certainly having something on top of the cards will reduce the risk of cards being accidentally mucked, but it is important to educate players that even
that may not eliminate the risk completely, especially if the player is sitting beside the dealer. (It also doesn't help that some players like to place their blind/wager on top of their cards and push them forward when they fold, which is a horrible practice that also confuses dealers).
I do not see a problem with returning the cards to the player if they are clearly identifiable and retrievable. Also, if the dealer did something very egregious, I have observed some venues consider doing something like providing a refund of a tournament entry or something like that off the table. However, when it comes to making the ruling at the table, whenever cards that have not been tabled are mixed in with mucked cards, the hand would be dead. The cards should never be fished from the muck. To preserve game integrity, there can be no other solution.