Just a thought experiment...
There is a fairly well-known technique where in certain sequences one partner might make calls that respond to an implied RKCB 4NT call that is not actually made. For instance, you might agree to play that a transfer followed by a 5-level call is an immediate answer to an implied but not made 4NT asking bid from partner. I.e., 1NT-2D, 2H-5C as three key cards, hearts agreed. This auction resembles 1NT-2D, 2H-something, 4NT-5C. But, the 4NT call is not actually made. Instead, Responder in a sense assumes an implied 4NT call for his calls.
Another similar example is a call after a quantitative 4NT, where the meaning of the 4NT call shifts from quantitative to RKCB, in a sense. For example, 1NT-2D, 2H-4NT, 5D. 5D as an RKCB response to 4NT is assuming a change to the meaning of 4NT from quantitative to RKCB. That auction resembles 1NT-2D, 2H-4NT, 4H-4NT, 5C. An insufficient bid, perhaps, but the point works.
I wonder to what degree assumed bidding might be played in other auctions.