Laptops at conferences: Good or Bad?

I don't get out much but at the two conferences I've attended over the past year, both on tech subjects, I'm amazed at how many participants are tuned into their laptop w/wireless internet access instead of the speakers. Is this a good thing or bad, I don't know. Do you think it originates from college classrooms over the last five years, where you see all the students with an open laptop? Reasons I've heard on the pro side:

1. My boss would never have let me attend unless I could be connected, respond to emails, or code up that web page that is due on Friday.
   
2. I'm taking notes! Duh.
3. I can work on the laptop and listen to the speaker a the same time. This is the era of multitasking you know. This proposal for my next consulting gig is due tomorrow.
   
4. I'm one of the upcoming speakers and need to tune my slides.
5. I don't really want to be here; the boss made me attend. Thank heaven for internet access to keep me entertained.
   
6. I'm the gal keeping the running blog on what's happening here. Variation of #2 above.
7. As a family man, I'm just taking advantage of the free wireless here to stay in touch with what's happening at home. Balanced work/family stuff is important to me.
   

In my experience, #2 doesn't always ring true based on the number of yahoo, google, cnn, AIM chat, etc. sites that I see up. For #3, ask yourself if you're doing work or just random browsing.

And the con side:

1. It's got to be disheartening to the speaker to see all of the faces buried down on the screens and shoulders hunched over, typing on the keyboard. Of course, many of the speakers do the same when they're in the audience, so maybe they're all used to it.
   
2. It could just be a little annoying to neighbors trying to listen to the speaker, to hear all of the keyboarding going on around them.
3. Your neighbors are also distracted by web pages appearing around them. Your email, chat transcript, or favorite team sport site is very interesting but I'd rather focus to the front of the room where the speaker is.
   
4. It's possible that you're getting only a percentage of the speaker's message. If it was important enough to attend, why not resist the connection urge and give all of your attention to her/him?

I also think there are some common personalities that you see on display for this subject:

1. [The Tough Guy] I always have my laptop open, period. If I'm there, I'll be using it. Case closed.
2. [The Tinkerer] I'm trying to get my stupid wireless working. It was working at the hotel, can't figure it out. I've changed my WEP settings a few times each time requiring a reboot, but it still doesn't work. Maybe I need to re-install a driver?
   
3. [The Flaunter] This US $3000 17" MacBook Pro is nice, you'd have to agree. I'd better be using it, for what it cost me!
   
4. [The Conformist] Most everyone else has a laptop here. I may as well have mine open, too.
5. [I bought the mobility dream] In those commercials, innovation and inspiration always happen in front of a wireless laptop. Can't I participate in that, too?
6. [The First Web Page is Free] The hyper-connected type who probably can't admit that she is addicted to the internet
   
7. [The Single Point of Failure] My company/enterprise/division/group will fail unless I'm online and available at all times.
   

Has anyone ever attended a conference or a large meeting where laptops are asked to be put away, much like cell phones are? If you've spoken in such a setting, does it bother you to see the heads down?