I would like to turn on BitLocker encryption on a remote computer I don't have physical access to. What I am afraid of is that:

• The operating system will not be able to boot after enabling BitLocker (for example, will stuck on some screen asking for password, key or something like that and will need a physical access)
• The operating system will encrypt all the drives, not only several of them selected by me
• The operating system will automatically encrypt every drive plugged in in the future

How justified are these fears?