Nor does DL do flying out of BKK anymore! Some of the airlines that fly as DL codeshares have very limited hours of operation so you would only be able to check your bag three hours prior to your flight time, like Korean and, IIRC, Shanghai/China Eastern. There are limited hours that the check-in desks are staffed and, in fact, the desks are used by different airlines at different times so the signage changes. You literally have to sit and watch this happen if you show up early.

I have left bags with Chubb in Bangkok and it was a quick, easy process.