I think I know where they could have gotten the idea.

In re-runs of old gameshows, it's not unheard of for them to edit the clips to look like the prize is Insert Sponsor Here, when the prize is actually something different. You can really notice this on Kid's Gameshows when the prize is something like an Xbox 360 for a gameshow that took place in 2002. (When a PS2 would be fair more likely)

However that's for RE-RUNS of PRE-TAPED SHOWS, meaning the person who won the original prize got the original prize and original airings would have shown said prize. The only "change" would been purely for advertisement purposes only.

That's very different from "You're getting an all-expenses paid trip to the Bahamas!" and then backstage they say "And here's an old Terminator T-Shirt or something, the one we had in storage that doesn't have the custard stain."

Which is very much what this situation was.

They probably heard about this practice and assumed that they could give a fake prize that's sponsor friendly, and then the real prize is something far less extravagant. Which tells me that they did not run this by their lawyers.