Congratulations to UN and others who already matched. It is early, but if you have an offer from a school you like, and it is an exploding offer, why wait? This happens all the time. Sometimes for personal reasons, like a spouse's job. Sometimes not wanting to move outside of the US.
She should update the schools she has been talking to about accepting an offer to be fair to them. Then schools with sufficient resources may still fly her out to "see" her research. Others may cancel. In either case, I admire such candidates who can say "I do not need to be at a top school to do decent research, neither do I need to keep the market waiting and backlogged for 3 months for my decision."