Here's my question:

If you give to a friend or relative an Amex card linked to a Plat or Cent account, they're supposed to benefit from the insurance that comes with the main card. Would that still be valid if let's say they held a personal Amex card (green or gold for instance) linked to their personal band account and paid with that personal one for vacation for instance?

Would the rule that states "you benefit from the insurance of the highest Amex card you hold whatever the one you use" be enforced since the cards wouldn't be linked to same main card holder?