When I heard of the stunt I immediately thought it was a stunt as well. If security is so lax that someone could break in and get to the top I dread to think what terrorists / vandals could do.
Ref funding some more information : http://www.brightoni360.co.uk/latest-news/blog/the-brighton-i360s-funding-explained-and-how-the-scheme-will-boost-the-local-economy/