As theories go, it is at least no worse than your belief that Ann Eaton made the scratches on the the
aga and fooled both the police and the other relatives.
Incidentally, I have never made such a claim that Ann Eaton fooled the police. To say that I claim that is a strawman argument.
It was not the polices job to scrutinise and pass judgement on forensic evidence. Its their Job to secure the scene, collect and pass on any forensic evidence to the forensic staff at the lab.
We don't know what the police involved personally think of the silencer. With the exception of Stan Jones and Miller as they have made their views known to us on TV shows.
Stan Jones and Miller both express the view the silencer is genuine. Stan Jones comes across as a right cretin so that answers why he thinks its genuine. Miller on the other hand expresses the view that the silencer is genuine because the lab told him so.
As far as the lab is concerned, we know that they did not understand the dubious circumstances it was found in since DI Cook handed it to them under the pretence that Stan Jones had found it. We know from Mark Webster that Hayward had never seen backspatter in a silencer before. We know from Fletcher's testimony that he does not understand the subject of backspatter very well. And neither has he seen backspatter in a silencer before either. Thus the lab fooled themselves. Millers belief is based purely on circular reasoning.
There probably are members of EP that think what I think. But they wont dare express that in public would they? I wonder who Bill Robertson thinks planted the blood?