Here's some more information from my TA:
The package is only available for groups from approved travel agencies. The open bar program is exactly that, there are minor limitations; wine is only available by the glass, beer can only be served 1 at a time (no buckets on other promotional packages) and certain high end liquors are not included.
Most of us are pretty good drinkers...maybe not as good as our friend Dave the Wave...but we try. Those friends who I travel with frequently have an average bar bill (for a 7-night cruise) anywhere from $700-$1500/couple.
Yes, we're cruise alcoholics....