See Asimov's ideas on creativity - it is essential for the production of new ideas that team members feel they are in an environment where "stupid" ideas are not mocked. For every 1 good idea it's fair to imagine there might be 10 daft ones. The more ideas in circulation the better - and it also gives people with daft ideas an opportunity to have them challenged in a constructive fashion - which may lead to them developing the kernel of their idea that might not be so daft.

    http://www.openculture.com/2014/10/isaac-asimov-explains-the-origins-of-good-ideas-creativity.html