‘play anything’ has two important issues:
1. it commands dummy to participate in the play. L43A1c prohibits
dummy from participating in the play. You can add it up.
2. the law provides for a defender to select the card in such case.
The problem is that by doing so declarer obtains inferences that he
may capitalize upon and gain from. Thus, the ‘so-called penalty’ can
at the margin instead penalize the defenders.
If the penalty also included a loss of a trick, declarer will remember
to never ask dummy to participate in the play.
As far as the defenders not knowing that there is something to be
gained by the penalty, that’s the way the cookie crumbles.
regards
axman