This is a bit more difficult than it sounds to implement if we're talking about all buttons. Only thing I can think of that would grey out all buttons would be having Amelia not sleep for 25+ hours.
Do you remember which buttons or where Amelia was when this happened to you? I can probably allow main buttons to be pressed while sending a diary saying it failed instead, though I don't know how helpful that would be and if it might just clutter and confuse what's going on.