I can't imagine doing something similar for work. Are they paying you all the time you are away (after all, you are basically "at work" the whole 24 hours).
It just seems another way to squeeze more house out of people.
That's the normal life for a lot of people who attend conferences etc. If that's not for you, that's fine. Just don't take that sort of job.
--> Many of them have fun elements to it to relax the attendees and give them a break. Infact, breaking the regular 'work more' pattern is the key aspect.
--> Any trip is always hectic - whether work or personal. If you can get more done during a 3 days trip which will help you to spend more time with the family once you are back, it is better in some way. Right :)