Developer Libraries » Panic

While technically, an app only needs to accept ACTION_TRIGGER Intent@s in order to work with the panic framework, @ACTION_CONNECT and ACTION_DISCONNECT should also be required since they set up the two-directional TOFU trust association between the panic trigger and the receiver. If a panic receiver only implements ACTION_TRIGGER, it can't set up the TOFU trust association that happens as part of the ACTION_CONNECT config sequence.

But if an app did not want any user setup, but instead wanted to pin the trusted apps and automatically use them when they are present, then those apps do not need the TOFU stuff.