No they do not have copies of every Bitlocker key.

Bitlocker by default creates a 48-bit recovery code that can be used to unlock an encrypted drive. If you run Windows with a personal Microsoft account it offers to backup that code into your Microsoft account in case your system needs recovered. The FBI submitted a supoena to request the code for a person’s encrypted drive. Microsoft provided it, as required by law.

Bitlocker does not require that key be created, and you don’t have to save it to Microsoft’s cloud.

This is just a case of people not knowing how things work and getting surprised when the data they save in someone else’s computer is accessed using the legal processes.

Her other series are great. Tower and the Hive, Acorna, and the Tales of the Barque Cats. One of my favorite authors.