Forum OpenACS Development: Re: xotcl core cr procs throw out assigned item_id and assign a new one, why?
As mentioned before, be aware that you have to care about the validity and security of the passed id, since one cannot trust on from-data.
Jim: i see you point, using the fresh item_id as a "poor men's transaction code". i would not rely on this without further checking. The the storage operations in the db are quite late for double-click prevention, and not particularly well suited for meaningful error messages concerning double-clicks.