I do this frequently without issue. In the past couple months:

My friends got married. For their honeymoon, they cruised the Mediterranean, starting in Venice. They flew in a couple days early and stayed on my points without issue.

My niece was looking at colleges. She and my sister stayed at a couple hotels using my points without problem.

As has been mentioned, MegaBonus and CC certs work differently, and specifically state the member must be present.