If you’re whitewater kayaking, it’s not uncommon to have a knife accessible from your PFD.

It can be used to cut any ropes you might be tangled in or (worse case) cut the PFD.

In general, having a knife with you is useful in most emergency situations (and a throw rope, pin kit, plus knowledge of how to use them).

edit: Oops, this was supposed to be a response for the parent thread.

… and I want my headphone jack, back.

There was another thread (which I cannot find atm), which said that the author cannot make an Android port, because due to the nature of android (or Google?) the android app would not get the same level of privacy as in the iOS version.

edit: I found the link.