It's often illegal for a company to disclose that they've been compelled to provide information to law enforcement. So many companies had a warrant canary which said they had not been served with a request for information.
Reddit for instance removed their warrant canary 8 years ago
Yeah, that's the gag order aspect. I think we should have protection laws in place to determine how many times, say, in a quarter, a company is asked to comply with surveillance requests. Nothing to hurt any investigations, just to service us as due notice.