Security and Ajax

I know forms submitted via ajax that the security component does not work. (Checking for edits / tampering)

 

What is the reason for this? I understand if you add fields dynamically why it would not work because of the hashed fields when the form is rendered.

 

But if you are simply sending a form as coded $this->Form as standard procedure, no edits or fields added why would it not act the same?

The exact data is being sent as if it was submitted http. No?

 

Just curious.

 

Thanks,

 

Dave