Hmm. "What's that smell?" would be high on my list. Also, "Is that the fire alarm?" On a more serious note, what someone gets out of the workshop really depends on where she's coming from - her experience with GTD, what needs are pressing, etc. In other words, your list would no doubt be different from hers...

Note: You might have your person record the session for you. Also, David is usually hard to access because everyone wants to talk to him. However, he usually has a handful of coaches with him, who are great for answering questions. If you have a big list of questions, I'd suggest going to them instead of David himself.

Finally, you might find the following tips useful - From Getting the most from David Allen's RoadMap seminar:

* Do your research - In Learn more, faster, he recommends thorough research before the event.
* Arrive Early - Meet the staff!
* Move around the room at each break - He suggests asking people if it's OK to switch seats. One gets a different experience from each location.
* Don't feel the need to write too much - This seminar goes fast, and others have blogged about it in some detail.
* Stay open - Some people tune out when they hear something that sounds like it doesn't apply to them. If that situation occurs: a) ask yourself why you don't want it to apply, and b) search for a way for it to apply. Connect the parable/story to something you've experienced, or might experience. Stay an active and engaged listener.
* Bring 150 business cards, and try not to go home with any.

Also:

* Choose carefully - talk to someone who has previously attended.
* Combine travel with other events/possibilities in area.
* Decide successful outcome - reflect on goals and objectives.
* Be an active listener - listen for nuggets of information that you can use. Look for easy-to-implement high-impact ideas.
* Bring questions/problems for Q/A, and introduce yourself when asking.
* Make contact with the presenter after the session is over.
* Socialize - Never eat alone. Collect and pass out business cards, but be discriminating, jot a reminder note on the back, and follow up afterwards.
* Follow up - call locals on attendees list you didn't meet.
* Share within your organization - let others know what you learned (basic overview, plus learnings).

Cheers!