On Mar 16, 2:55 pm, wrote:
IIRC all tournament openings are shown to be a draw. IIRC further the
other openings are not selected in tournament play because they gave
one player a too large advantage.

Almost.

First, what Schaeffer did is to show that freestyle (unrestricted)
checkers is an absolute draw.

He has not analyzed all of the 3-move restriction openings so he has
not proven that tournament checkers is a draw. He has proven that
some of the 3-movers are a draw, and will likely eventually show that
all 156 of the accepted tournament choices are a draw (the other few
are almost certain losses and are not used). Of course, there could
be a deeply-buried surprise in one or more of the 156, but with the
amount of other computer analysis done to date, it's not very likely
--- but it hasn't been categorically proven yet.

But translate this over to human players, and checkers is certainly
not a draw when played by real people, even at the very highest
current level of human skill. So people are going to keep playing.