Steve, writing "[ad_conn user_id]" is
your code. The fact
that it happens to call the ad_conn proc, the implementation of which
is part of OpenACS, is no different than the fact that Oracle running
on Linux makes function calls to the Linux kernel.
Back in the old days, aD sure wrote a whole heck of lot of custom code
for all of its many clients. Often that code was entirely propietary,
owned by the clients who paid for it. Clearly the lawyers for both aD
and aD's customers thought this was just fine. However, this was
usually the typical "GPL ACS, plus custom code for our custom site
which we don't distribute to anybody" case.
Now, there may have been some, but I personally don't recall any aD
client who wanted to re-distribute their custom code. My guess is
what Don says above would have been aD's (and aD's lawyer's) position
as well, but I don't know. Maybe the other OpenACS consultancies have
had a customer with this situation? It does sound like something a
nervous-about-open-source IT manager would ask...