axman, on 2019-December-08, 09:28, said:
Don't know what your antecedents are. It is notable that if by some route that the OLOOT is rejected 57C3 makes it clear that the subsequent OOT play performs the function of lead. It also is notable that knowing both of declaring side's cards the only possible gain to the defenders to rejecting the lead is when it is important to declarer's RHO which card the LHO plays first.
Law 57C3 says "a premature play(not a lead) by declarer"
The effect of this is that when Declarer plays to a trick before his RHO and the lead to that trick was made by LHO or Dummy then Declarer's play may not be withdrawn regardless of which card RHO eventually plays to that trick.
However, if this play by Declarer is actually a lead, as is the case when Dummy's LOOT is withdrawn, then Law57C3 explicitly does not apply.