Boon of Safety

• WOTC Official Reminder Textofficial rules
  Scry — Look at the top N cards of your library, then put any number of them on the bottom of your library and the rest on top in any order.

• WWizards of the Coast2022-04-29
  Official Ruling
  Removing a shield counter in this way isn't the same as regenerating a creature.
• WWizards of the Coast2022-04-29
  Official Ruling
  If the target is illegal as Boon of Safety attempts to resolve, it will be removed from the stack and its controller will not scry.
• WWizards of the Coast2022-04-29
  Official Ruling
  “Shield” is not an ability that creatures have and shield counters are not keyword counters. If a creature with a shield counter loses its abilities, the shield counter will still protect it as normal.
• WWizards of the Coast2022-04-29
  Official Ruling
  A creature with a shield counter on it may still be destroyed by state-based actions if it has damage marked on it equal to its toughness or has been dealt unpreventable damage by a source with deathtouch.
• WWizards of the Coast2022-04-29
  Official Ruling
  If a permanent with a shield counter is dealt unpreventable damage, that damage will be dealt and a shield counter will still be removed.
• WWizards of the Coast2022-04-29
  Official Ruling
  Shield counters don't prevent players from sacrificing creatures.
• WWizards of the Coast2022-04-29
  Official Ruling
  If a permanent that would be dealt damage has more than one shield counter on it, that damage is prevented and only one shield counter is removed.

Rulings via Scryfall