Does "This replacement effect may apply more than once to the same event" ever matter?

Question

There are two instances in the Magic: The Gathering comprehensive rules that say that a replacement effect may apply more than one time to the same event:

717.6. If a card with an Astrotorium card back would be put into a zone other than the battlefield, exile, or the command zone from anywhere, instead its owner puts it into the command zone. This replacement effect may apply more than once to the same event. This is an exception to rule 614.5.

903.9b If a commander would be put into its owner’s hand or library from anywhere, its owner may put it into the command zone instead. This replacement effect may apply more than once to the same event. This is an exception to rule 614.5.

Before the rule change that caused commander death to be handled as a state-based action rather than a replacement effect, this could clearly change the way in which cards that say "exile it instead of putting it anywhere else" interact with commanders. But that can't happen now that commanders can actually go to exile.

With the current version of the rules, are there any situations in which the rule "This replacement effect may apply more than once to the same event" actually has an impact?

Answer 1

No, there is currently no such interaction. The rule serves as a catch-all to prevent any such interaction in the future, so that a commander/Astrotorium card can never change zones without its owner getting the choice to move it to the command zone instead.

Rule 903.9b creates a replacement effect that moves the commander to the command zone. Its purpose is to guard against other replacement effects that could replace that movement event. For example, consider the following scenario:

1. My opponent casts Unsummon on my commander, returning it to my hand.
2. Rule 903.9b allows me to replace that effect with a move to the command zone. I choose to do so.
3. A hypothetical replacement effect reads as "if a card would move to the command zone, shuffle it into its owner's library instead". It applies to the event created by 903.9b.
4. Normally, my commander would now be shuffled into my library without me being able to prevent it, because 903.9b has already applied to that event. However, because of the exception it can apply multiple times, and I may again choose to put my commander into the command zone. I do so.
5. The hypothetical replacement effect cannot apply again because of 614.5, and my commander is finally put into the command zone.

To my knowledge, there is no replacement effect or chain of replacement effects that replaces moving a card to the command zone with moving to hand or library instead, and so step 3 of the above scenario can't happen, making the exception to 614.5 currently unnecessary.