Is there such a rule:
get out of the car = get out the car
out the bagbag = out of the bagbag???
Recently I've come across some British native speaker video, he wrote idiom: "let the cat out the bag"bag". I commented that there should be the preposition "of". But he answered "You'll see that 'of' preposition dropped in all sorts of 'out of' expressions. E.g 'Get out the car!'"'".
So now I don't understand. Does this "rule" really exist and I can drop "of" in 'out of' expressions?