I think that would just encourage contestants to buzz in immediately, since I imagine that the risk of penalty of not knowing a question pales in comparison to the reward of getting to answer for a strong contestant. You effectively eliminate the only downside of buzzing early since contestants would get to hear the entire question regardless.
The traditional College Bowl <TM> / Quizbowl <not-TM> technique is (a) to assign a 50% penalty to the early buzz with an incorrect answer, and (b) since it's game with teams and has two teams, the rest of your team is disqualified from answering the question, leaving the opposite team with lots of time to think about it (and subsequently secure access to the 3x bonus question following every toss-up question.)
Which is lots of fun and very competitive, but a little bit less tele-savvy.
Ack, we ran up against a "celebrity" reader in the final rounds of a Quizbowl tournament who didn't stop reading reliably when the other team buzzed in. I don't know how, but the other team was really good at taking advantage of this, buzzing in before the reader had given enough information to answer the question, and then answering after he'd finished the sentence. Our team got steamrolled.
In Highschool Quizbowl, I'd take advantage of the fact that most untrained readers have a hard time stopping mid-syllable, or even mid-word, so any time there was a question that hinged on a single word, such as a world capital question, I'd buzz in on the first letter of the word, and they'd usually get out 2 syllables before stopping, providing enough information.
Q: What is the capital of L-(BUZZ)-ithu-- [stops reading].
A. Vilnius.
But if they had had really good reaction time and stopped on L--, I'd have been hosed. Latvia, Lithuania, Liechtenstein, Libya, Liberia, etc...
