For rewards booking there should be no issue! For IHG, Marriott, Hilton my friend and I travel all the time together on my rewards points and he always seems to arrive before I do! I make sure I put his name on the reservation as well. I never stop by the front desk nor have they ever asked if I ever showed up! I have done this 3 separate times this summer with IHG. I do call the hotel like a hour before hand to double check my buddy is on the reservation and to let them know he is checking in first.

If your wife has the same last name as you it really shouldn't be a issue!