I was always told 'if you make a customer a promise - treat it as a contract'.
Another story of competitions and loss of trust? This time it is in the upmarket glossy magazine market. Country Life Country Living recently ran a competition to find a new columist. They had announced that that the readers would be able vote for the winner from amongst the magazines blogger community. Midway through the competition the editor changed the rules and decided the winner would be selected by magazine editorial staff and not the readers. Worse was that those shortlisted by the editorial staff were not necessarily recognised as being valid by the blogging community.
Not sure what is going on there but seems a real 'own goal' to get an active part of your readership interested, change your mind and then seemingly rubbish peoples skill and judgement when justifying what you did.
Story source: Press Gazette