RCD Accidental Trigger Guard

This is to prevent accidental physical triggering of a non-integral RCD, without affecting its normal operation in any way.

I live in a block of flats (or apartments, if you prefer) where there is a communal services cupboard for everybody's gas and electricity meters, and for the consumer units (fuse boards) for all the various communal and private circuits within the building. It's kept locked but the key has to hang outside for access by the emergency services.

Some of the meters are o