> Personally I have my lists set to CONCEAL by default; the reason being is
> that we don't want our competitors to be able to access potentially
> valuable mailing lists.... the most active users are already known anyway.

This is exactly why LISTSERV has the option Review= Owners
This keeps all prying eyes from seeing the subscriber list.

Way back when dirt was fairly new and there were no spammers or address
harvesters to worry about, many lists use to be set Review= Public
As time progressed CONCEAL became a more important option to some
subscribers. Today it is vital, ONLY if an inexperienced list owner used
Review= Public or Private.

> On the other hand it does make some management tasks a pain, such as having
> to use GET to review the list of members

Huh?  If you use the below command, you get a list of everyone, concealed or not.

REVIEW listname NOH ALL

The bottom line folks:   Unless you have a VERY good reason to have
Review= Private or Public (which I can't think of one)  Review= Owner
should be used. This completely eliminates the need for Conceal for
subscribers.  If Conceal really bothers you, periodically set everyone to
Noconceal. That is of course if you don't like or can't remember the  ALL
option when you need to Review the list :-)