In another topic "Just quit quietly - the law is on your side" there was a lot of discussion about how to leave quietly without getting tagged publicly as "no longer a JW"
Here are some legal cases that could be used to show support for leaving quietly.
You have to first send a letter saying you're leaving that specific congregation, and that you don't want them to keep records of you.
If the BOE says anything against you here are some court cases that make precedent for bringing a suit against them:
Baugh v. Thomas (1970)
Bear v. Reformed Mennonite Church (1975)
Guinn v. Church of Christ (1989)
Where the U.S. courts upheld a judgment in respect to limits of disciplinary actions by non-profit religious institutions of their members and non-members.
Basically if you withdraw from a congregation, you can hold them legally responsible if they retaliate against you for doing so.
This makes for a situation where they cannot DF you for leaving the congregation.
Since you aren't DF'd they won't make the "no longer a JW" announcement.