Another explanation for the coffins locked and secured from the outside might have been people “mistakenly” buried while comatose or otherwise still alive.
As most know, this was not unheard of during the Victorian era.
Doctors were still perfecting their craft. Sometimes a body would be buried inside a coffin with a little bell attached onto the interior lid.
The idea being if someone were to awaken inside a dark coffin, all they need do is to pull a string, makes the bells ring and let the Mortician know of his unfortunate error.
Thus came the phrase; “Saved By the Bell”. That would make a nice bedtime story for the little ones. Don’t you think?
**Thus came the phrase; “Saved By the Bell”***
And later Bateson made a small belfry that was placed on the grave. The waking dead person had a string in their hand to pull the bell if buried alive.
It was considered such a joke that the term “Bats in the Belfry” became a phrase for people with odd ideas.