Is it fair to have public design competitions being entered by design professionals?

After my post yesterday highlighting The Royal Mint’s new design competition to design a 50 pence for the 2012 London Olympics I came across a story on the Design Week website: Royal Mint to Launch Olympic coin competitions
Which details that there has been some negative feedback from the design community after the launch of the competition and that The Royal Mint…

“is expected to launch a series of tenders in the build-up to 2012 to find designs for the backs of coins celebrating the Olympic Games.
The news may quell some negative reactions that have risen from the design community following the launch yesterday of the Royal Mint’s public competition to find designs for the backs of 50p pieces.

A Design Business Association spokesperson says, ‘Commercial design businesses should not give away creative ideas for free. In the current economic climate it is more important than ever that design businesses maintain a healthy profit margin. To do this, they have to be paid a reasonable fee for the work they do.’“

Much respected designer Michael Johnson founder of Johnson Banks had a few words to say about the design competition:

“Michael Johnson has branded the competition a ‘nightmare’, and says that the consultancy will not be entering any designs for the 50p piece.
‘A competition like this is a lottery – the Royal Mint would get a far better result if it short-listed six good design groups and paid them £5000 each,’ says Johnson.”

The question that Design Weeks article is asking is:
Is it fair to have public design competitions that are being entered and won by design professionals?
The story goes on to say…

“Recent public competitions have seen the appointment of professionals rather than members of the public:
July 2008 – Mayor of London Boris Johnson’s A New Bus for London competition, which resulted in victory for Capoco Design and Foster & Partners
September 2003 – London 2012 launches a competition to design the capital’s bid logo to win the Olympic games, appointing Kino Design in November 2003″

So what do you think, should professional designers be entering these competitions?
They obviously have an unfair advantage against non professional members of the public.
Be interested to know your thoughts on this..