I appreciate everyone's replies. I shared the very same concerns--that, even if alcohol was just a trigger for an underlying psychiatric problem, alcohol should have been totally off limits.
Perhaps her therapists feel that if the underlying psychiatric issue is "controlled", then alcohol would not longer be a trigger?
I also have the same concerns about medication interactions.
On the other hand, how can I call her out on the issue when she has had about a year and a half without further incidents? She used to have a crisis every 3-6 months.
I'm not sure how to really push the issue if there have been no problems that long.