Originally Posted by
HongKonger
Imposed by DL, not KE?
Also OP, how many tickets do you want? Often there's only one. I'm doing a search recently where KE shows up as an option if I search for 1 ticket but not 2.
KE sets blackout dates that are specific to regions/routes/directions. DL then takes those dates and says that if even a single flight on KE is blacked out by KE for that date, then every KE flight is blacked out that day for awards and upgrades using DL miles.