Well, if they ever succeed in making money they'll find another way than this one:
Virgin Express has a block seat agreement with DAT on the CPH/BRU service. Fine. A mate of mine was travelling full fare business class CPH-BRU last saturday, but was denied boarding as the aircraft was full of VEX pax ! Indeed, they sent him CPH-BSL-BRU with Crossair.
How on earth they'll ever make a profit by turning their own full fare pax down, in order to cater for the competitors low fare pax is way beyond me.