I did this last year. I got a flyer in the mail, (thought) I'd read it closely to confirm that no timeshare presentation was required, and signed up.

When I got there, after checking in I was immediately sent to a representative who asked me what time I wanted to reserve for the presentation. I was pretty confused about it, and it was awkward, so I signed up for the least intrusive time I could think of.

Showed up at the appropriate time, and immediately explained that I wasn't interested in buying in. The kid (mid-20s) was eager, and I think he thought he could sway me. The tour took something like 90min, and every step of the way, my response was some variation of "This looks great. Thank you, but I'm not interested".

Last part of the presentation is when they sit you down and write a bunch of numbers on the board, telling you how great a deal you're getting (lol), etc. The kid brought in the sales manager, who did the whole "OK, what would you like to sign up for?" thing. For the millionth time, I told them I wasn't interested, but this time I (offhandedly) added that I told the woman at checkin that I wasn't interested either. The smile disappears from the sales manager's face. She says "She was supposed to tell you this wasn't mandatory". Gets up and walks out. No handshake, no goodbye, nothing.

So essentially, I told everyone I wasn't interested every step of the way, and was ignored. When it finally got to the end and it didn't go their way, I was kicked to the curb.

Thing is, I'd probably do it again if I was given the opportunity. I'd just be adamant that I wasn't interested in the presentation, and then go an enjoy Maui.