In life and bridge, one's choices are frequently restricted, but the outcome often useful and/or instructive. Consider, for example, the positioning of the sheets of paper containing the starting line-ups for last night's first session of the mixed pairs final. Unfortunately, space considerations restricted the choice of where the four sheets could be placed, but on and adjacent to the left hand automatic door was soon discovered to have drawbacks. If the door was activated while you were trying to read the lineups, it was very frustrating, but it was highly am using if you were observing such a scenario. Of course, at the bridge table, 'restricted choice' has certain connotations.

                    Game All. Dealer East.

                         S  Q J 3
                         H  K 4
                         D  A 9 8 3 2
                         C  9 3 2
         S  A 7 6                      S  T 8 5 2
         H  A J 8 7 6 5                H  T 2
         D  7 5                        D  K Q J
         C  J T                        C  8 6 5 4
                         S  K 9 4
                         H  Q 9 3
                         D  T 6 4
                         C  A K Q 7

          West      North       East        South
                                Pass        1NT
          2H        2NT         Pass        3C
          Pass      3NT       All Pass

At one table in last night's final, South opened 1NT and, after West had overcalled 2H, North went through a Lebensohl sequence to show a raise to game with a heart stop.
West led the H6 and declarer won with dummy's king and played a club to the ace on which West followed with the jack.
West was likely to be short in clubs and restricted choice principles seem to suggest a subsequent finesse of the seven but, of course, this is not a true restricted choice situation since West could be false carding from JTx or simply making a come-on signal for hearts.
Unfortunately, declarer judged to finesse the C7 and was soon four down. The opponents' actions can restrict one's choices as witnessed by the following hand from the first session of the final.

                 North/South Game. Dealer East.

                        S  K Q J 9 7 3
                        H  A J 9
                        D  A 8 3
                        C  6
         S  5                        S  A T 4
         H  Q 8 7 5                  H  K T 6 4 3 2
         D  Q J T                    D  7 4
         C  K 9 7 5 2                C  8 3
                        S  8 6 2
                        H  -
                        D  K 9 6 5 2
                        C  A Q J T 4

At one table, East opened 2D in lieu of a weak 2H and West responded 2S to play in 2S or 3H depending on partner's major. North could not double for penalties, so had to choose between passing and then showing his spades or doubling to show values and then hoping to show his spades later.
He chose the latter course, but East, for whatever reason, chose not to retreat to 3H. The evidence of her hand told South that East had hearts, but the evidence of the auction told her that East had spades. If she had passed, so presumably would West and seven down would have persuaded East as to the wisdom of showing her suit in future.
However, South chose to believe the auction and bid a constructive 3D and North now had a problem. In light of East's "known" spade suit, it seemed pointless to bid any number of spades, so he shrugged his shoulders and bid 3NT.
East led the H4 and the sight of dummy must have made North feel sick. He won West's HQ with his ace and advanced the SK and had the minor consolation of seeing East win with the ace, thereby enabling him to at least make his contract and gain some matchpoints at the expense of those who had gone down in 6S.