I'll throw in a bit of calculus here too. Let's say you are going for a one-week vacation, which is effectively 6 days when you lop off time travel. Say that your total vacation budget is a conservative $4,000 for your crew. That is roughly $670 dollars per day of fun. (Fill in your own numbers here)
Now, a timeshare presentation will knock a half-day off your fun time. I know they say it is only an hour, but by the time you get to presentation, eat the cold breakfast, talk to the sales guy for an hour, spend another hour actually getting them to release you from the presentation centre so you can get your comps, transport to the park you want to tour, it WILL be noon or later. So the cost of that presentation is about $335 to break even, but there is also the cost of lost fun experiences to consider as well; you're also losing a big chunk of time when you could be doing something better. Most people do leave in a bad mood as
@Lisa P. says, so the rest of your day may be clouded too. To be safe, I would want the savings to be at least the cost of one day's vacation.
So calculate out what this 'savings' may really cost you before you decide to go to a presentation. Usually, (almost always), it doesn't make sense to us, but sometimes the offer can be sweet enough. Our last presentation was in Mexico where our time touring an ultra-lux golf resort (miles above our pay grade - saying no was easy) was compensated by them covering our SUV rental for the week and a free sunset dinner cruise (which was a wonderful experience, making up for the lost morning). The tour itself was very 'lifestyles of the rich and famous' and included watching whales breach from the balcony of the penthouse suite! This was a very unicorn experience though; I wouldn't expect that kind of experience at WBC. Maybe 'lifestyles of the sunburnt and mouse addicted.'