User Interface: Do I need a certificate or not?

The confirmation email says:

 

Marriott Rewards Redemption, certificate required at check in.

 

And also says:

 

Additional Reward Information

 

For hotel reward e-certificates:

Since this reservation is using Marriott Rewards points, no paper certificate is required at the time of check-in. All you need to do is arrive for your stay. You may however, print this as confirmation of your upcoming redemption reservation.

 

The reminder email says:

 

Marriott Rewards Redemption, certificate required at check in

 

Please be prepared to turn in your certificate for your stay.

Done