A venturi effect can happen with gas though too Haligan...all it requires is flow. Since gases are compressable as opposed to liquid the exact math involved is a little different, but still the same effect.
Scientific theory aside....I've got a few of those Winchester NT cases with the large flash hole in .45ACP and haven't had any problems with them. I do keep them segregated from my standard brass and they're only used for light cast bullet loads.
I think in a low-pressure situation they are fine.
Now in a high-pressure load or cartridge I would not use any brass that has an enlarged flash hole.