cannibal,
I may be wrong here but I think you may find that the so called maintenance organisation and the operator are the same entity.
If that is the case I think it puts a slightly different slant on the defence espoused!!
Irrespective the operator is responsible for the maintenance of their aircraft and the buck stops there.
A problem with the grease causing the whell to fall off???? wow some grease. Grease that does that is called glue.