Or maybe I mixed it up?

Maybe it used to be schengen->non schengen and nonschengen->schengen both required screening, and now, schengen->nonschengen no longer requires screening, but nonschengen->schengen still does?

Can somebody tell me which of these 4 (schengen->nonschengen now, nonschengen->schengen now, schengen->nonschengen 2 years ago, nonschengen->schengen 2 years ago) require(d) additional screening and which do/did not?

Thanks!