Originally Posted by eyecue

You cannot opt out of the standard pat down that you will get for opting out of the AIT.
If you get selected for AIT you will be in front of the checkpoint. If you decline then you are asked if you are opting out and you are told that you will receive a pat down that is a least as thorough as the AIT. IF you decline that then your property may be searched anyway. You are then asked to leave and escorted from the screening area.
When you are accepting a standard patdown, you get the right to be screened in private and you get to have a witness of your choosing present with you. I hope that answers your questions