By all indications, use of this provision is extremely rare, nothing like the number of NSLs issued in the US. So it would be a big ask, but it could happen if the consequences of wide disclosure were 'extremely grave'.

For context, one of the motivating leaks was when there was a planned 5am counter terror raid, and someone in the state police leaked the who/what/where to a major newspaper, who had papers coming off the presses at 3am about people who hadn't been raided yet.