from a controller point of view this isnt the big hero event everyone wants it to be. my reason, watch and listen to the radar tape recording. when the controller noticed that the A340 pilot over flew the final onto the parallel final what was the first thing she did!
she spent 6 count them 6 seconds telling the pilot that he over flew the final when what she should have done was to seperate the aircraft FIRST, THEN and only THEN can you tell the pilot he F'ed up. they were lucky that day had it been a little diffrent those 6 seconds may have been very important.
Aircraft flying at opposite directions to join parallel finals are separated by 1,000 feet, specifically to prevent a situation where aircraft like this miss their turn to final at the same altitude. The aircraft flying southbound to join the left-side runway final is separated by 1,000 feet from the aircraft flying northbound to join the right-side runway final.
Standard Operating Procedures, at least in my observation, essentially dictate the phraseology to deal with aircraft failing to intercept the final or, in the case of a dual/triple ILS or ILS-PRM approaches, violating the no transgression zone.
Of course, if you look at the radar tape, the only thing we can discern -- and with a degree of uncertainty at that -- is that the aircraft may have come 900 feet instead of 1,000 feet. Frankly, that is all on the pilot. If you can't use an airport diagram and/or figure out runway numbers without impeding on the centerlines of the wrong runway, you're putting a lot of people at risk. (I'm speaking from the perspective of an IFR pilot).