Right. Going in is actually the last resort, for trained youth anyway. We were taught "Reach, throw, row, go" in order of preference. First, lay flat on the dock and stick out an arm or leg (reach). If its too far, then throw a line with a floatation device (throw past the victim, not at them, and reel the line in until they grab it). Third, take a boat out if available. Lastly, go out yourself if absolutely necessary.
To be clear, that's what Boy Scout lifesaving training taught you, not what HN taught me.
It's dangerous to attempt a rescue technique based on a vague memory of a forum comment.
Get trained, like Joe did.