Mura CMS : Examples of how to intercept User creation, update and save events to do some processing of the User Bean and then create custom error messages as well.

muraUserEventHandler.cfm

<cfscript>
public any function onBeforeUserCreate($, event) {
	var user = arguments.event.getValue('userbean');
	// do some processing of the user 'bean'
	// to create an error message, just add any key to the end of the User's getErrors() struct:
	user.getErrors().createFailMessage1 = 'UserCreate fail message goes here. Sorry #user.getFName()#.';
}

public any function onBeforeUserUpdate($, event) {
	var user = arguments.event.getValue('userbean');
	user.getErrors().updateFailMessage1 = 'UserUpdate fail message goes here. Um...#user.getFName()#...whatcha tryin to do?';
	// maybe you do some more processing of the data and have another error...
	user.getErrors().anotherFailMessage = 'Another fail while attempting to update the user...so here is the message.';
}

public any function onBeforeUserSave($, event) {
	var user = arguments.event.getValue('userbean');
	// if you need access to the original userbean
	//var originalUserBean = arguments.$.getBean('user').loadBy(userid=user.getUserID());
	var originalUserBean = arguments.$.getBean('user').loadBy(username=user.getUsername());
	// 2 = user, 1 = group
	if ( user.getType() == 2 ) {
		user.getErrors().saveFailMessage1 = 'UserSave fail message: Hey #user.getFName()#...not gonna happen.';
	}
	// you could check for errors, and even _replace_ the error message...
	// for example, maybe there's a duplicate username
	if ( StructKeyExists(user.getErrors(), 'username') {
		user.getErrors().username = 'Hey, the username, #user.getUsername()#, is already being used! The email address associated with the account is #originalUserBean.getEmail()#. If that is you, then reset the password by entering the email address in the form located at <a href="./?nocache=1&display=login">HERE</a>.';
	}
}
</cfscript>

Theres a typo on line 20: user.getUseranme() should be user.getUsername()