Question

I was in Jerusalem within the walls.
I went into the home of a rabbi. After some time, a few more Torah scholars gathered. They sat as a religious court, discussed whether to blow the shofar or not, and decided that in Jerusalem—certainly in the Old City, and all the more so in places from which one can see the Temple Mount grounds—there is a Torah-level obligation to blow. And the rabbinic enactment not to blow does not apply, since from the outset in the Temple they did not decree against blowing. Moreover, they enacted that in the presence of a religious court one should indeed blow. And here they are a religious court, so there is a Torah-level obligation to blow here [through positive action], and the rabbinic prohibition not to blow does not apply [as a passive omission]. And there were many other arguments that… I don’t remember.
The religious court ruled to blow.
They blew.
Immediately afterward, they proclaimed an excommunication against anyone who would reveal who blew,
because he has a daughter in a seminary, and there was a reasonable concern that the activists and their long arm would throw her out.
 
My questions are::

1. Are they right, and does one need to blow?
2. Does the decision of excommunication take effect? [Beyond the usual prohibition of malicious speech?] And what does it mean for someone who violates the excommunication? I would be glad for the Rabbi’s answers.