Generally they can buy and sell at will as long as the events are filed with the SEC. However, if they were to make an extraordinaty sale/purchase just before material news came out that immediately affected share price, they would most likely be investigated for insider trading. So there's the answer to Brewski, there has been some big announcements that they couldn't make due the quiet period. Since they wouldn't know when the quiet period was actually going to be over they couldn't place the buys you so badly want them to place.
That theory is just as probable as yours implying they have no faith in the company.
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