Is your country not in the combobox? Is an ad coming on top of your video? Is the button disabled?... :)
P.S. These tricks are usually harmless (or at least they should be). Most of the times they deal with unimportant client-side content. One rule of thumb though, if you are the creator of a website - make server-side security checks if certain actions change states in the server! Client-side 'prevention' is useless precisely because of tricks such as the one above.
P.P.S. This can easily go into the subject of Cross Site Request Forgery (or rather how to protect against it)