The losely wrapped blanket was on the garage floor for two months and had been moved several times by Michael Paine... it's a miracle that the rifle didn't fall out by itself. With kids playing around the house a rifle could have been exposed at any moment.
Who said the blanket was wrapped loosely?
Michael who also respected Oswald's privacy, moved the package and thought it was camping equipment.
And as for the children, a rifle without bullets is just a big stick, personally I'd be more worried about what appears to be a big fixed electric drill or bandsaw.
JohnM