Shouldn't this intelligence and control be on the MME? Ideally SGW is not supposed to call the shots. Bearer Release from the network perspective is usually achieved by network initiated bearer release or network initiated detach. Never heard of a smart SGW :D Interesting though . . Waiting for others to respond.
Cannot, the SGW just forward the signalling from/to PGW. PGW can initiate the bearer release for some reason, for example related to the charging issue.
What factors derive such limitation ?