SkredlitheOgre
Explorer
My current DM actually forces players to do it that way. No taking combat casting unless you've already been successful at some defensive casting without the feat for example. No taking catch off-guard unless you've actually been improvising weapons on occasion, etc.
When I DM, I run this rule, but only if the party are in the middle of an adventure when they level up. If they level between adventures, then I just say that they've had time to find someone to teach them, or been in a bar fight in the context of Catch Off-Guard. That's just me though.