We use a ground anchor on all upright memorials. Using a ground anchor means that even if a joint fails the headstone will only fall gradually with effort placed upon it.
New technologies have made securing headstones more reliable and safer using resin and stainless steel dowels.
Cemeteries and Churchyards now regularly check headstones for stability. If there is a situation where the gravestone becomes unsafe the resposibilty is on the owner of the grave. Using these methods ensure stability for the future.