1) They're sales presentations with the sole purpose of selling you a (or more) timeshare.
2) Doesn't matter what they're called, i.e. "Owners Updates", "Vacation Survey", "Informative Resort Overview", etc....they're sales presentations. Refer to #1.
3) Unless you accepted the "gift" in terms of a discounted stay, cash, tickets or anything else, you are not required to attend whatever they're calling it. If you do accept the stuff, then don't act surprised or get belligerent when you find out that the salesperson is asking you to buy something, Refer to #1.
4) There's no excuse for you if you haven't done a modicum of research into the timeshare before attending a sales presentation. Google is your friend.
5) If it sounds to good to be true it is.
6) Stay away from the words "free", "perfect", "always" and "never." Free and perfect don't exist and always and never are exceedingly long periods of time.
7) If you do buy something at a sales presentation, understand your rescission rights. And don't cry if you didn't read the paperwork until 30 days afterwards.
8) Lastly and most importantly...if 4 months after you purchase, you get around to figuring out that you a) can't afford the monthly payments, b) can't afford the annual fees, c) have no idea how to make reservations and/or d) come to the realization that despite what the salesperson said owning a timeshare might NOT be cheaper than renting a hotel don't go crying to blogs, forums, etc. screaming SCAM. Make no mistake, there are scams out there. And blogs, forums, law enforcement, etc. will all listen and help when possible. Don't confuse scam with you not doing your due diligence.