Drupal tightens up node_load()
The other day we had an error on our Drupal 7 site where users would receive error messages whenever they tried to register for a conference. The site would register them, but the only thing the user would see is a JavaScript dialog box with an AJAX callback error message with some code in it; since the users didn't know that the site had registered them, they kept clicking the register button, getting registered multiple times. Not a desirable state of affairs.