Dgad,
yes - I did. About 18 years ago. First I was suspicious about this too. The big magnetic rings relatively close to the tiny magnets inside the cartridge,....hmmm.
However, - as the tests showed (and some measurements done at the technical high school Munich) the 2 magnetic rings are embedded inside two steel "rings" which do very effectively shield the magnetic field - at least from dispensing vertically towards the platter surface.
There was no detectable interaction with the magnets in cartridges nor did the test show any induced hum.
It performed flawless with a very wide range of cartridges from Ortofon MC-5000, Supex, Koetsu, FR, Grasshopper v.d.Hul, Dynavector,Kiseki, Ikeda EMPL, SPU and Miyabi.
The Verdier is a fairly "raw" concept and was from its very beginnings as a DIY-project introduced in the late 1970ies in the french L'Audiophile-magazine. It is however a smart design which gives - proper set-up - extremely good sonic results and has some very clever design features which all do work for the better in performance (if not in looks....).
The versions built prior to 1993 are sonically better to later production.
The versions with pure magnetic bearing in the horizontal plane - no added ball.
I am referring to the La Platine Verdier only.