For example, some wedding cards have Allah's name written on them in some form, such as Bismillah. As these will be discarded of by guests (some non-Muslim) at some point, who will be responsible if the cards aren't treated with care? Also, flags such as Saudi's and Iran's also have Allah's name on.
As some of these can be abuse by non-Muslims, who does the responsibility of ensuring there is no misuse fall on?
No one is. You can dispose of anything that has Allah's name written on it if you don't need (newspaper, official documents, etc..). I only see it a sin if you do it out of disrespect.
The prophet PBUH used to include the name of Allah on all of his letters of where he used to send them to people including non Muslims, knowing they would dispose of them.
That is my opinion, however, there is an opinion from Shikeh Bin Baz that says that all letters MUST include the name of Allah as the prophet said and that the punishment is on the receiver if they dispose of it, as stated in the following fatwa:
However, I do not agree with such opinion as we never heard anything in the time of the Prophet, his companions, or their followers of special way to dispose of such items, which common sense would say they do dispose of them.
