Relevant part of ABF regs:
Quote
Certain types of conventional calls or treatments are considered to place demands upon the opponents’
defensive preparations. The conventions/ treatments in question are categorized as ‘Brown Sticker’ (BS).
Any one of the following characteristics qualifies a convention/treatment as BS if it is a matter of partnership
agreement:
a) Any opening bid of two clubs through three spades that: could be weak and does not promise at least
four cards in a known suit.
Exceptions:
(i) Where all the weak meanings guarantee at least four cards in one known suit and only the strong
options do not.
(ii) A two level opening bid in a minor may show a weak hand with 5+ cards in either major only, or
as an option among any number of strong hand types.
b) An overcall of a natural opening bid of one of a suit that does not promise at least four cards in a known
suit.
Exceptions:
(i) A natural overcall in no trumps.
(ii) Any cue bid that shows a strong hand.
(iii) A cue bid in an opponent’s known suit that asks partner to bid 3NT with a stopper in that suit.
c) Any weak two-suited bid (whether it be an overcall, an opening bid or a response) at the two or three
level that may by agreement be made with three cards or fewer in one of the suits.
It seems the 2NT = Weak clubs or strong balanced does not qualify as 'brown sticker' because of Exception i.
Is this correct? I wasn't sure if I should post it in the Laws section or here.