This has been a past challenge, and while rules are clear often makes it a trade off to use the free night. If a globalist you could in theory book free night in another name if traveling with others, but this while allowed would run risk of changing rooms and possibly being in limbo for a few hours if you can’t overlap late check-out and early check-in options. Often the suite has trumped the putting certificate to separate use. But agree YMMV situation.