language analysis to enforce code standards

[Jason S. Friedman]

Hello, I administer the Informatica ETL tool at my company.  Part of 
that role involves creating and enforcing standards.  I want the 
Informatica developers to add comments to certain key objects and I want 
to be able to verify (in an automated fashion) that they have done so.

I cannot merely check for non-emptiness; that is trivial to circumvent. 
  On the other hand, I probably do not need to be able to catch 
developers who are determined to not create comments.  There are not too 
many of them and perhaps they will find it is easier to write a (useful) 
comment than to game the system.

Any thoughts on how I might proceed?  Stated plainly, how can I tell 
when a string more-or-less forms at least one phrase?