Assumption of guilt.

It's not a court ordering evidence of innocence, it's just the BSA saying either show us that you're innocent or we'll _start_ legal proceedings.

Not law, no legal precedents required, a simple "naff off" or "see you in court then" would suffice.

A court will want to know the basis of the accusation, if that consists of "company X wouldn't tell us about their software configuration" they'll be shown the door.