Uwe,
no, your opinion is correct. The rules clearly state that Leica equipment should be used for photos displayed in this forum. There have been numerous discussions about the understanding of "equipment" and I believe the term stands for itself and means either a body, a lens or both. A filter would not do...
We not do proactively search for non-leica photos but hope and encourage everybody to obey these rules. As everywhere in life you have some falling through the grid...
best - Klaus