I am sure many people have had problems using public phones or even personal mobile phones near to milatary facilities or when they are flying overhead and this could be a very big problem when calling the emergency services. I am sure also that a quite different could occur when people with mental health problems or problems with life in general use financial services and similarly this could occur with some children. As well as being an activist on many leftish causes I also write stories and am preparing some postcards around these stories.
The art idea here is similar to that of an artist who linked up a community that could not contact each other with her choice certain brands and have come with the Nuttle ice cream drawn version and just lick em in one of my stories.
For children and people who have had problems calling emergency services due to the noise of milatary aircraft or pehaps even civilian aircraft I will use at the side of the aircraft a helicopter symbol. Whilst for the children and people who have had problems entering bank note-think of a hole puncher and I will also use a security marker to create a flyer as if for a party and with text around the subject of disability.