I've been reminded of this recently on Signature Service flights... I've seen FAs pouring the "untouched" Prosecco back into the bottle once PDB service was completed (that is, when they were done serving the PDB, but not necessarily collecting all glassware/swapping with plastic cups).
It reminded me of this:
https://onemileatatime.com/emirates-...ing-champagne/
I'm rather indifferent... but what do others think here?