The way I suddenly saw it as while reading this thread is this way:
Solar Flare Dragon and
Command Knight both say that they can't be attacked if there is another monster on the field. If that other monster is the same monster, then neither can be attacked and Life Points too cannot be attacked. This is because that when considering one of the two cards, the other monster on the field can
potentially be an attack target. Therefore a monster must be attacked, since there's a monster on the field that can potentially be attacked, according to one of the cards.
But when you consider the other monster, you find that it too can't be attacked, and that the first monster you looked at is now a potential attack target (as it is now considered "just another monster"). So there's a potential attack target on the field, so you must attack a monster on the field.
So you must attack a monster, but you can't. There's no option of attacking Life Points directly instead. This is the lock for
Solar Flare Dragon and
Command Knight.
Marauding Captain says you can only attack him. Fair enough. But when there are two of him on the field, and you're considering one of them, the effect of the other states you must attack the other instead. So you can't attack the one you're considering. When you consider the other, the same thing happens. There's a monster on the field that is a legal attack target (indeed, it begs to be attacked, but that's beside the point), so you must attack a monster on the field. Attacking Life Points is, again, not an option.
The Legendery Fisherman cannot be an attack target whilst Umi is on the field. If he is the only monster on the side of the field, there are no legal attack targets on that side of the field, so Life Points must be targeted instead.
In conclusion, I say that Konami rulings are wrong. True, they worked fine enough before, but now they should be changed a bit. Instead of:
The attacking player chooses 1 of their monsters and designates 1 of the opponent's monster as a target. Play then proceeds immediately to the Damage Step, returning to the Battle Step if the attacking player wishes to attack again with another monster. If the opposing player has no monsters on the field, the selected monster's attack will inflict Direct Damage on the opposing player's Life Points (Direct Damage).
I suggest that the emboldened bit be replaced with something like:
"If the opposing player has no potential legal attack targets on the field, the selected monster's etc. etc. etc."
Until now the two phrases have meant the same thing. But with these locks, the phrases now have different meanings. According to one of the cards of the lock, you
could attack the other monster (or itself for MC), but only the effect of the other card prevents that from happening. There is a monster that can
potentially be targeted, but it turns out that it actually just can't.
