How easy is it for a user to view the html code displayed in a html component. If it is easy is there a way to prevent it?
AIR doesn't provide any automatic or built-in way for users to view the HTML source of an HTML component. If you wanted that behavior you would have to add it in yourself. So there shouldn't be any easy way for users to see it.
(Of course, if you're just displaying an html file off the user's hard drive in your application (such as one included in the installer bundle of your app) then the user could find and open the file in the file system. But not from within your app.)