You need to be realistic about where this film is to going to be seen and conform to the laws of that country. It's folly to ask someone in the States or Germany about releases. If you want a lock-tight, international release because you're making the next $100 million dollar grossing documentary, then yes, get the most airtight release. Otherwise, you're just going to waste time and intimidate interview subjects.
In the US, news people do not need releases. Filmmakers do. On-camera releases are second best to written ones, and generally accepted for non-controversial interviews9"Boy, that show was great!")