Noob Check Valve Question

This question is really just to satisfy my curiosity. I am currently using a 3 piece airlock, but what about a one way check valve?

I have heard that sometimes primaries can suck the sanitized water/vodka through the airlock back into the fermenter. Why not use a one way check valve so nothing can get in, but the gas can escape? With check valves there is a certain amount of pressure that needs to be built up before they release any gas; the same principle goes with an airlock.

I assume the pressure needed for a check valve is greater than a traditional airlock and that this is why airlocks are preferred? But we all know what ASSuming can do.

Just curious!

chris white of whitelabs on a podcast for the brewing network, advised that as little pressure as possible be put on fermenting beer, so like for the first 3 days or so he recommended a cheese cloth even be put over the mouth of the carboy, that fermentation will be so strong that the C02 will keep any nasties from getting in there, then after a few days go airlock, the pressure affects the yeast reproduction

You would have to have a check valve that opened under extremely low pressure. Maybe an extremely light swing check. anything with a spring in it would be too much.