As long as I continue to hold the Amex Platinum card that qualifies me for the Fairmont PLAT5 promo, is there any reason that I can't charge our room stays to my wife's Amex Gold card and still maintain the promo?

The way I'm reading the terms, it says you have to pay for the five nights "using an American Express Card". It doesn't say my card, and it doesn't specifically say Platinum card.

Since my Platinum Amex earns MR points at the rate of 1.25/$1 on all purchases, but my wife's Gold Amex earns them at 1/$1 with double points at places like hotels, we should collect more points that way.

Thoughts?