You say the event is 2 hours this length of time can pose some problems mainly you are going yo need to change tapes at least once. the pick up shots of the crowd can cover the video on this, audio however is another issue as you dont want to loose any part of the speeches.
If there are breaks in the program then perfict, but if all they are doinig is changing speekers that might not be enuff time to change tapes.
If you can record DTE using something like a Firestore drive you might be ok, however I would recomend 2 cameras and overlaping your tape changes (this also makes the video less stagnent and moor visualy appeling as you can cut between two different angles) And then for your master audio record to a seperite audio recording device capable of recording for the deration of the event.