Jonathan I don't know if there is a way to digitally trace the money between banks so AMEX is able to determine these type of practices.
Peter Yeah, perhaps some sort of restriction or specific Bunq account setup for Amex where you can only make purchases, another option could be to have the possibility to link it the AMEX card to a bunq account, online cards or Maestro/Visa cards would do the trick. maybe top-up functionality is not the right fit for Amex due to its special characteristics.
