[rt-users] Conditions error message

[Tim Bell]

I am writing a condition and would like to be able to give an 
informative reason to the user why the change of a custom field they are 
requesting is not permitted.

Returning undef gives me the possibility to stop the action but I can't 
see how to tell the user why.  I can log it into a system log file but 
the user does not have access to that.

Any ideas ?

Tim