At past SAP and ASUG conferences, free water bottles were distributed to attendees. Not only is this expensive, they are often used once and then thrown away. To show an alternative, I will donate a membership to "Leave No Trace" for the first 5 people to answer this forum thread, on condition that you carry your bottle at the conference! Leave No Trace will send you a membership card and a water bottle. One of mine is shown in the following images:
If you aren't going to the conference, or aren't one of the first 5, consider supporting Leave No Trace directly via:
I've been a member for a few years, and helped Scouts in my local troop earn an award for their efforts, as well as presenting them with gift memberships. For current status, see:
p.s. you can carry the bottle on an airplane, but make sure it is empty at check-in!