Jorb made the announcement in the middle of a thread regarding a custom client's auto-hearth feature. After auto-hearthing was included in an Ender client update, this measure was taken to ensure that the game wasn't too broken.

Interestingly, the timer ended up breaking the auto-hearth feature in a much more severe way. Before the timer, when a person had auto-hearth enabled, his hearthling would hearth the instant an unknown character was detected. After the timer, this still applied... but the client would continuously scan for unknowns, and would keep restarting the hearth process. This action of hearthing, of course, stops all other actions being undertaken by the character, including movement. I saw three different noobies get killed, simply because their hearthling kept stopping in his tracks.