I am delighted to read that two better known Australian sparkler producers - Chandon Austalia and Seppelt - have switched to crown caps for their top wines:
I especially like the slip label around the crown cap down the neck reading
CROWN SEAL CLOSURE RECOMMENDEND SEAL FOR LONG TERM BOTTLE MATURATION
Especially the fact that Chandon has moved to this step could be a giant step to cork-taint-free sparklers worldwide.
M.