Learned it the hard way at the first timeshare presentation I went to with my then-husband hoping for outback dinner coupons. Presentation ended at 11pm and then they were "look at this offer, we'll meet you halfway but only today, offer expires at midnight" we bought the damn thing :(
Yup. Job offers do this all the time too. Even the smartest people have trouble responding to a ton of information in a short timeframe. If someone refuses to give you the time to think something over, its because they're scared about what will happen if you get time to think.
We'd been up since six am, were nervous about needing to get home and relieve my parents from babysitting, and hadn't ever been conned like that in the US before. Never made that mistake again. I managed to sell it for 10% of what we'd paid right before 2008 (whew).