Originally Posted by NotJustDreaming

I used to do this all the time with no problem. With certificates and points redemptions.

BUT,

Recently, I booked a Marriott hotel in Toronto for myself and my adult daughter - two night stay using points.
I added her name to the comment area on the reservation.
And, I reached out to the hotel by email when my international flight was delayed and asked them to let her check-in in my absence as I'd be arriving in the middle of the night.

Big fat no.

Phone call to the hotel was also a big fat no.

Apparently they are protecting my Bonvoy account - anyone could be using my points for a reservation.

Proper way to do it is to call Marriott and have them book the redemption under the guest's name.
When I called Marriott, they said the same thing - protecting my account and it's a relatively new policy.

I would not risk it after my recent experience.