Bulger's a bit of a different case altogether though. In his case, he was able to take out "insurance" so to speak. Even if you compare him to Scarpa, Scarpa's handlers were found to have not been aware of the sheer magnitude of his criminality, unless you believe that DeVecchio was indeed as guilty as he was charged with. In the Bulger case, FBI agents were found to have actively supplied information to Bulger which helped him continue his enterprises and commit murder. Less "turning a blind eye" than becoming complicit themselves.

A rats a rat though, I guess it's just semantics beyond that. Why do you refer to Bulger as a "punk" though? Aren't they all "punks" by that distinction? Especially, in this particular case, Steve Flemmi who was already an informant? Bulger had already served a lengthy sentence by the time he was providing information to Rico and Connelly. Less "afraid" of prison and more just not wanting to have to go back, it would seem. He'd already spent many years at Alcatraz, amongst other penitentiaries. He was scum, for sure, but punk connotates, I dont know, some sort of weakness...? And I wouldn't call Scarpa or Bulger weak. More rat cunning and calculating, if anything.

More on topic, Pasquale Barbaro aka "Il Principale" was an Australian boss who flipped in the early '90's after he'd left his wife to marry a 23 year old Filipino woman. He was later murdered, but provided a lot of information to authorities while he was not actually facing any charges himself. Granted, the family of his spurned wife (Agrestas IIRC) may or may not have been after him.