2-3 could be used if an official was really confused.
Case 3.1.1 indicates that the withdrawl of a player is not permitted, but with no penalty given.
By stretching the imagination that 10.1.9 *Delaying Returning* may be interpolated/extended to include an inadvertent shortage of participants, as well as an act of deception, other officials could affect a technical foul.
[Willful] refusal to follow the 5 player requirement (with the exception of starting the game) may be penalized by determining that intentionally disregarding R3.1.1 could be an unsporting act.
However, if we use the general 10-1-8 "Commit an unsporting foul" [
because playing with less than 5 players is specifically unaddressed] and look at Case 10.1.8 Situation --> Comment:
(A Specific Unsporting Act) and use selective wording "...was the result of confusion, the entire procedure would be followed except no technical foul would be charged.",
Then, I think, we may have the intent of the rule of requiring 5 players on the floor; instead of penalizing the inadvertent act of playing less than 5 players, we simply require the participation of 5 players, much like we require one ball with sufficient air. 
mick