You just have an inexplicable obsession with this "one turn shield crutch" thing Eternal, something that happened like 1 time and with players that don't even bother with BoP anymore nor are in it. If you hadn't even mentioned it, people wouldn't even consider it existing, there's very generally common sense with these things here.
Your comment just doesn't make much sense. No country aside from like german small states would let themselves get annexed in 1 year regardless. A demobilized Austria, Poland, France, Spain, Sweden, Denmark, Portugal, GB, etc etc would at the very least defend themselves with forts and militias. Then again they could lose a great deal of their territory, almost losing the war thus, hence putting them in great handicap and that is their punishment.
It's frankly unrealistic for you to expect any country to fall in 1 turn. This isn't Poland in WW2 and noone's a blitzkrieging Germany.