It's a 7 year old tutorial, but no nothing with the workflows has changed recently. What are you wanting to do exactly? Force admin approval on/off based off a field value? Now that a Code action is available and it's possible to modify trigger variables by reference it's better to do this using API than a direct database query. Example as follows.
Global
Triggers: onBeforeUserConfirm
Type: Code
User: Automatic
Access: Everybody
Conditions
1: [cb_singlecheckbox] Equal To 1
Action
Method: PHP
Code:
Code:
$variables['var1']->approved = 0;
$variables['var1']->storeApproved( false );
Parameters
Reference Variables: Variable 1
The user object is available by reference to onBeforeUserConfirm so this should have no issue toggling them to needing approval. You can also use this to toggle them as approved by changing 0 to 1. This all happens before activateUser is called which handles displaying the message to the user after confirming so it should reflect that they're confirmed.