Some of the New York members believed he was, but Scarfo was able to save him by allegedly telling Joe Ciancaglini, that either he personally kill Sindone or he would also get the same treatment. Ciancaglini was Frank Sindone's right hand man in his crew, and served as his driver and bodyguard, they were made together in the family and were the last members made under Bruno's reign along with John Grande and Alfred Salerno. Like Sindone, he was a good earner. Testa and Scarfo knew Ciancaglini remained in contact with Sindone, speculation of John Grande informing them about Ciancaglini and Sindone talking on the phone, it would also explain why Scarfo wanted to make John's sons fast into the family. Nicky figured because John was loyal and informed them of those two, that his sons would be loyal too, but Salvatore flipped later on. Ciancaglini was close to Johnny Keys and Sindone that it would be impossible for him to not know something was going on at the very least. Ciancaglini most likely knew his life was in the balance during that time, and most likely tipped off by Patty Specs. So as soon as he was sent for, he knew what it was for.

Why Philadelphia did not cave in to New York (Genovese and Gambino families) was for these reasons I believe.
1. He was a tremendous earner and enforcer. Getting rid of Frank Sindone and Joseph Ciancaglini Sr would have weakened the family's North New Jersey operations, as Anthony Caponigro, and John Simone were dead. Scarfo vouched for him which was good enough for Testa that Ciancaglini would be loyal and fall in line.
2. He was close and friendly to many mobsters.
3. All soldiers follow their Capo's orders, even if he was involved, it would not be held against him (think of Vincent Gigante on the Costello hit).
4. There is no evidence he was at Bruno's shooting, he was at the hospital where John Stanfa was, but he did not go into the room or talked to Stanfa, just drove Sindone there and waited outside or in the waiting room.
5. The new Philadelphia administration did not want a hit parade, just the key conspirators, Capos and Caponigro. Yes 1982 was also a violent year for the family, but that was after Testa was killed and Scarfo took over.
6. I believe Philadelphia needed to flex a little to New York to show that one family does not dictate on what Philadelphia has to do, but follow only when the commission made a rule, or approved of an action. Phil was boss, but the commission made sure he stayed in contact with then.