The instances in which it starts getting a bit murky are those in which organised competitions are involved as opposed to competing in the mainstream marketplace. Some competitions are acceptable to professional bodies, whilst others aren't. The Design Institute of Australia states that: 'In general a professional designer should avoid providing their skills for free, except in genuine cases of charity or in competitions where there is no intent to avoid the purchase of professional services'. (www.dia.org.au, 2008)
The DIA seems to be concerned for the welfare of young designers and is trying to guide them toward consistent outcomes. when viewing sites like '99 Designs' it is clear that the designers are being taken advantage of. Its a demeaning process, putting your skills and ideas up to be scrutinised by people who just want a cheap job done.
One could argue that the competitors make a choice when entering "pitching" competitions, though this does not consider how the credibility of the "profession" is being undermined. I suppose what it comes down to is that when you make a decision to pitch-you are to some extent deciding the future of the profession.