LHO opens 1NT, announced as kamikazee (8-11, balanced). Two passes come to you, and you realize that your agreements are not exactly tailored to this opening. However, you have agreed to play that a double shows one minor or both majors, major calls are natural, and minor calls are takeout, of sorts. The minor calls show that minor and either just spades or that minor and two higher suits.
When the balance is 2♦, partner knows that you have diamonds and either both majors (Platonic ideal 1444) or diamonds and spades (would convert a 2♥ call to 2♠). When the balanced is 2♣, you will have clubs+diamond+hearts, or clubs+diamonds+spades, or clubs+hearts+spades, or clubs+spades.
Ugh! Well, shoulda coulda does not help here. You have to make a call.
So, suppose you have a hand where 2♣ is your call. After LHO passes, partner bids 2♦, which offers diamonds as a contract that is "acceptable," and showing presumably that his club support is not so good. Partner is expected to have some game plan if you convert 2♦ to 2♥ (to show clubs+hearts+spades) or 2♠ (clubs+spades). RHO, however, who was apparently sleeping, bids 2♠ out of the blue, which is alerted as a transfer to 3♣. Strangely, the opponents have actually discussed this sequence.
So, what now, if you want to compete? Should you not complete your pattern, in case partner, if he knows your pattern, has a better idea than 3♦?
Obviously, 3♣ sounds like a bad call. But, what should it show?
Well, think back to your possible hand types. It seems to me that flags come in handy here.
3♣ seems to flag hearts. 3♦, then, would seem to flag spades. Why would you flag a major? Because that's the only major that you hold. So, 3♣, to me, if Paradox Flags are in play, suggests something resembling 4441 and 3♦ suggests 4414. With 4144, 2NT comes to mind, not only because it covers the problem of not wanting to flag a specific major, but because it actually sounds natural after partner, in a sense, showed diamonds. Natural is good, in moderation. LOL
Yeah, but what about the club-spade hands? Double seems to scream out. As a bonus, it is both penalty for the artificial suit and for the suit shown. Kind of cute.
Now, obviously this is a contrived, but nonetheless possible, example. But, the principle is similar to the paradox situation described earlier. The notrump bid shows the holding that isolates the preference suit as the shortness. The available call is a flag for the higher-ranking suit, in that other case for hearts because a flag for spades is not particularly useful.
Note also that both examples so far have a strange result that appears. Natural calls in "agreed" suits tend to have incidental flag messages concerning rejected suits. However, calls in an agreed diamond suit may on rare occasion actually also be flags for spades.