This has recently caused a bit of a stir in my guild. Normally everyone would bring their own flasks (we tend to raid with 20-30 players), but with the new cauldrons we've taken to each handing 3 flasks to the main alchemist before each raid so he can create a Cauldron for everyone. The reasoning being that they cost 20 flasks to make but give 30 out. So in the long run it ends up being cheaper overall. The excess flasks from the first two raid days are used to make "free cauldrons" for the 3rd day.
The problem however is that nearly a 3rd of the raiding team are alchemists themselves and have the Mixology bonus, giving them 2 hour durations on their flasks. So even though the alchemists only use 2 flasks per raid, they still have to pay for 3. And the remaining charges in the cauldron are just going to waste. The view of the alchemists is that they are being told to throw their money away. The officers' stance on this is essentually "tough shit", and it's creating a bit of drama.
So how does your guild handle the cauldrons?