Is there any danger in caching forms, such as node edit, add, etc? I am playing with authenticated caching modules to speed up performance while logged in.  Currently I am using authcache.  However, authcache and other caching modules often have node add, node edit, and other (CRUD) forms excluded from the pages the module will cache.

Why? What is it about a form that it should not be cached? Is there any potential danger in allowing these modules to cache forms found in the authenticated areas?
Forms have unique build ids that identify a particular submission. Caching would defeat that and thus defeat Drupal's ability to detect duplicate or invalid form submissions.