I was writing a question on StackOverflow and accidentally submitted it early; I was trying to hit "Return" to accept a tag but instead I submitted my question. I then immediately deleted the question.
After I'd finished typing up the question anew, StackOverflow told me I'd have to wait 20 minutes, since I'm a "new" user and had already asked one question. But I hadn't asked anything; I'd written and deleted a question, only.
Your system should only throttle questions that show up on the system, and exclude deleted questions from the throttling. It seems like accidentally submitting a question is easy enough with your web forms that a lot of news users may fall into this trap.
(UPDATE: Apparently questions can be undeleted. I had no idea. I guess that's why they call me a "new user"! This is a very cool capability but most new users will not assume it's there. Maybe make this capability more discoverable. Or not.)