I don't know how the "test" was done, so I can only speculate, and if flown was simply being observed then I don't see how the proper passages could be plugged, since a crank has to be in a block for the passages to operate properly.
Your dash example is with air, air is compressible and the relative flow rate to cross section is entirely different.
An open passage would basically have the oil feed pressure dropping to zero, just like when cam bearings are toast. In that case velocity WILL dominate and momentum comes into play. However, working clearances in an oil system should never let pressure drop to zero. That's the big difference. If pressure is actually present in the primary galley, then velocity will not rob a passage of flow. It is possible to lose pressure in that galley though for a variety of reasons, but that does not mean the fix is to reduce velocity, it's to plug the hemmorage wherever it's happening! LOL
