rmac
At any time on the approach, even at 50ft over the keys, a good pilot should have it in mind that they should have to do so, and the manouevre is well practiced and safe.
Very good advice.
The lowest I've gone around was approx 15', when an aircraft commenced its take off roll on a taxiway across the runway I was about to arrive on - the pilot was also talking to another airfield at the time .... a strange story, but true.
As I had no idea of the PICs intentions, I chose to climb away and avoid a nasty incident.
As my former neighbour (A320 capt) used to say, you have completed the landing when the engines are off and the parking brake is on.