Sales Pitch and Legitimate Give-A-Way, But There's a Catch!

Two weekends ago, my wife and I went to an RV show that was put on by a dealer from the Buffalo NY area. There were many pamphlets and displays from area campgrounds with free sign ups to win prizes. "Enter to win $10,000", "Enter to win a $1,000 gas card", "Enter to win a new Truck" etc. We filled out forms for a few of the give-a-ways and then enjoyed the show. This week, we have had calls from two different campgrounds saying that we won a $50 gift card for service or items at the RV dealership who put on the show and were "semi-finalists" for the big prize. All we had to do is set up an appointment and either sit through a 90 minute presentation about the one campground or take a tour of the other campground. They both made a point of saying that this wasn't a time share deal, we were under no obligation to buy anything, blah blah blah and we could leave after the tour/presentation and take the $50 gift card. We aren't going to either of the campgrounds mainly because it would cost us nearly $50 in gas just to get to them and back home. At the one campground, the woman said if you don't want to tour the campground in the next couple of weeks, we can give you a free weekend stay and give you a tour then. I asked if we could come and look at the campground and then stay the weekend with the tour at another time and the answer was no. Do a lot of campgrounds use this tactic to entice campers to buy a seasonal or annual membership? We are new to this lifestyle and want to enjoy ourselves and unwind. Not feel pressured by campground owners to buy something.