1 - if its a default view, you should not be able to delete it. You should only have the option to Enable or Disable it. If the enabled view is alter then you only have the option to Revert.
2 - An unaltered default views are not stored in the views_view table of the database (however they are stored in the cache_views table). If you alter the view, they are now stored in the views_view table.
So, if you have a unaltered default view and you make changes to it in the code, then the changes will be visible once you clear the cache. If you have an alter default view, you must revert it for it to match the code in your module.