I'm not surprised. A large number of people believe they can save the eight spots in line for an attraction and invite their extended family to come enter those saved spaces right before boarding the ride.
I think the proper response to people saying "we're saving that for people who will show up later" is to respond that you have been saving that same spot since first thing this morning, when you were there and declared "I'm saving this spot" and then wandered away to do other stuff. If they say you can't save a spot without physically being there, checkmate, they just admitted they cannot save that area because the people who are supposedly saving it aren't present.
Truthfully, I think a lot of the parade spot saving is just people trying to bluff their way through. They say "that area is saved" and if you walk away, great! If not, it's not like they plan to do anything about it. What can they do?