For my 2c...
You can look at this two ways:
One, it's only a week. A week of rest will let her body heal, and she will actually probably come back better than when she left. If she was working on a few skills, her brain will have that time to figure them out. The negative side, though, is that she is missing a week of work-outs: which could be introduction to new skills (etc...). However, it's only a week...
On the other hand.. she can still go to the gym, and do only upper body/core work. Swings on bars, handstands, positioning drills, etc.. As long as she is staying off her affected foot she should be fine. After a week, depending on her and how fast she heals, she may still be "hurting" after a week, and need a few more days. What you don't want to do is make a simple injury worse.
In my opinion, talk to her coach and see what his game plan is. If he wants her to vault or tumble right away, I would say keep her out. If he is going to ease her back in, and just keep her in for conditioning etc... she should be there, especially if she is part of a team.
Generally, I side with parents (unless they go against my judgement to keep the kids safe).