I do not have huge balances in the programs, probably between the six airlines' programs I am in, I have less than 150k total miles. Since the decline in my business travel, I simply do not accumumate them at the same rate. I put most points from credit cards in SPG and just do not worry about it. I do not spend any extra money to get miles except for the $30 annual fee for SPG Amex. At this time, I have received enough free travel from miles and points, that if I lost every mile and point that I now have, I would still be way ahead of the game and I would not at all regret having played the miles game. I am not a person to take mileage runs to get points, though I may take a trip that I want to take anyway if the points are good - it was worth it for the trip alone. So as disheartening as it would be to lose miles, I do not worry about it. If I get miles, I get them, when I need to use them, I do. I do not see them as a travel 401k, they are simply an available pool to buy airline tickets and hotels whenever I want to take a trip.

As far as funnelling miles to Hilton from AA if AA were to be under fire, I assume that, as others said, that this door will close. Hilton used to take miles from CO, DL, NW, and UA but all of those doors have been closed. I dumped some orphan miles to Hilton right before they closed.