After searching for an answer in the forums i figured this out for myself so thought i would post this easy solution to hiding the target audience field in forms.
(I have a workflow that automatically assigns one so i don't need users to be able to see or mess with that field)
Actually all you need to do is edit the column setting from within the content type of the list (you can can choose required, optional or hidden for target audiences).
List Settings>Advanced Settings>"Allow Management of Content Types" choose Yes
Return to List Settings, under 'content types' click on the name of the content type (ie: event), then under the list of columns choose "target audiences' then 'hidden'