My husband is 1/3 of the IT support (or 'computer dudes') here at work, so he has to be able to get to his email while on vacation. He also has to bring his phone along with him, which I don't like, but I can't do much about. He is always on call, since, without fail, there is always a coach or administrator traveling who is having internet or computer problems.
I like to have the laptop for the same reason, since my coaches are way to dependant on me. I usually have at least one email with the line, "and where do we keep the spare pens" or "I ran out of recruiting packets" or "where are the stamps?". I was smart enough to not give them my cell phone number....
It also came in handy on our last trip when the kids that were with us got bored, and they were able to go on to disney.com and play the kids games on there.