Must be because Amex - Taj vouchers being very popular and more on Taj stays. They have partnership and denying on utilising it is tough to swallow.Now Taj Reservation Booking themselves ask "Are you going to use any Amex voucher" the moment you say yes they will say "Discounted rates not applicable". If we say "No" only than they are providing Discounted rates. If we book Discounted property weather Amex would be redeemed or not ? Also you can use Amex or NeuCoins (anyone) for redemption !