This is reverse engineering in the same way that I redraw a map of my drainage pipes when there's a leak in my house. My plumber is not going to sue me and neither will Bose.
They won't sue. They will just threaten to do that and the OP will need to decide if he can afford to "engage" with them even if he may technically be in clear. To argue that reversing a protocol is not an issue you'd need to be in front of a judge and it's expensive to get there.