A question was once asked in the forums about how to stop WYSIWYG content from being wrapped in HTML p tags. Below are the steps to solve this problem.
1. Using JDeveloper (for 11g SSXA) or Site Studio Designer, open the element definition for the WYSIWYG in question.
2. Check the box for “Do Not Enclose Text in Editor”.
The 10gR4 Site Studio Designer Guide has this to say about the topic:
Do Not Enclose Text in Editor: Used to define how carriage returns are handled in HTML. If text is enclosed, each time the contributor enters a return, a paragraph is created. If not enclosed, a line break is inserted for each return.