2 taunting elf and lure

[Jelly95]

I know that if I have 2 taunting elf in play and attack with both of the elves then defending player can choose which one to block.

Does this change if I put a lure on one of the taunting elfs?

[Arix]

Everything that can block an Elf has to, but the defending player gets to choose how to split them.

Lure doesn't change anything.

[Urza]

Based on the following rule, defender has to have all his creatures block the taunting elf which has lure:

509.1c The defending player checks each creature he or she controls to see whether it’s affected by any requirements (effects that say a creature must block, or that it must block if some condition is met). If the number of requirements that are being obeyed is fewer than the maximum possible number of requirements that could be obeyed without disobeying any restrictions, the declaration of blockers is illegal. Tapped creatures and creatures that can’t block unless you pay a cost are exempt from effects that would require them to block.
Example: A player controls one creature that “blocks if able” and another creature with no abilities. An effect states “Creatures can’t be blocked except by two or more creatures.” Having only the first creature block violates the restriction. Having neither
creature block fulfills the restriction but not the requirement. Having both creatures block the same attacking creature fulfills both the restriction and the requirement, so that’s the only option.

[Jelly95]

why?

[Urza]

Because blocking the taunting elf without lure would fulfill one requirement. But blocking the taunting elf with lure would fulfill 2 requirements, which in this case is the max requirements that can be fulfilled. So any other declaration of blockers is illegal.

[Arix]

Indeed, that's how it works. My brain wasn't plugged in.