I called the Agudah and they said that there is a blackout in New York and new Jersey. I don’t know if that means the catskills are included in the blackout.
In sporting events, if the event is sold out the blackout is lifted. I don’t know if the siyum is soldout and if it is I don’t know if they wil lift the blackout and allow other venues to show the siyum.Perhaps if enough people call the Agudah at 212-797-9000 maybe they will add other venues.
If there is a blackout in NY/NJ, the Catskills is included. That being said, you make a good point that if it is sold out the blackout should be lifted everywhere, as there is no purpose for it any more. And this way those who would like to view it, can, as they can no longer purchase a ticket. (And the siyum is not encouraging anyone to stay home by lifting the local blackout.)