During a recent software launch, we added a screen that presents an updated technology agreement and put accept/decline buttons on it. After you decline a certain number of times, your manager starts to get an email. The agreement is not actually optional - all users must accept it just like they must accept the email policy, the technology usage policy, etc. By displaying a "decline" button, we inadvertently made it appear optional.
Perhaps we should have given them a "Defer" button and allow them some number of grace logins before they had to accept. This would've given them time to print out the agreement and review it so they understood what they were reading. However, just like the shirnk wrapped EULAs that come with software, this agreement is mandatory and should have been positioned as such.