As others have said, having noreview as the default setting is the 
way to go. Generally, I quiet delete suspicious subscribers (taking 
note of whether they are on mail or digests) pending an investigation 
as described below.

First part of the investigation is to do an Internet search of the 
suspicious subscriber's name, e-mail address, and ISP domain name 
(google search of the web and newsgroups; and sometimes a "whois" 
<http://swhois.net/> domain search). If results are ambiguous (they 
are not obvious spammers), I write them directly with a note 
something like this:
---------------------------------------------------
Hi, xxxx,

I was wondering why you joined MEDLAB-L as you do not appear to work 
in the clinical laboratory field?

Note that list policy prohibits address harvesting and spamming:
http://www.ualberta.ca/~pletendr/MEDLAB-L.html#4

Please drop me a note to clarify. Sorry to ask but we have been 
burned by companies who join and then harvest subscriber addresses 
for spamming, recruiting, and other commercial purposes.

Thanks.
---------------------------------------
If I do not hear back, that's it. Sometimes a person will reply with 
a satisfactory explanation and then they are re-subscribed quietly. 
This process works well for me.

Cheers, Pat
UA: http://www.ualberta.ca/~pletendr/
TraQ: http://www.traqprogram.ca/new-on-traq.asp