> she should have got access to the account, without having to demand it via discovery.

Even if she can (which is probably the case), she wants to go through discovery so there is a paper trail of going through a process. If she does this by any other means she depends on them to have the records of that process to prove she didn't have access to the account at the time. By going through discovery there is a trail of when she transferred access to her name and so it is on them to prove she had access to the account before that date.