It's not that it isn't concerning at all. It's a "known unknown," and most of us have already evaluated the increase and decided the risk is worth the potential reward. For my part, I'm content to wait for the specific explanation from the company if and when they elect to use the new shares.
Not all plans can (should?) be disclosed. What we're failing to see is that some things, even if legally disclosable, may be better left undisclosed for now, be it for competitive reasons or otherwise. You may not feel comfortable with that. I would prefer to know all about it, too, but am still willing to wait.
The specific types of contracts have already been kicked around quite a bit on this board. There's all kinds.
In... my... opinion.