Operators drum into pilots that they aren't to endorse MR's unless asking prior permission.
That's nothing new.. In fact it has been a less than redeeming feature of general aviation for over sixty years. I recall the situation where an LAME owned several trainers and put them on line with a flying school. A private pilot entered a serious defect in the MR and the LAME promptly directed the flying school CFI to ban that pilot from flying any of his aircraft. The word quickly got around and maintenance releases were always clean after that..