There is really very little opportunity for fraud because the shops entail taking a photo of the hotel's meeting board, which almost always have the date and the hotel name.
These are the hotel equivalent of supermarket scanning shops. You're not actually being invited by the hotel, but rather by a competitor which wants you to go in, not buy anything, and report back on what you found. I'm already at some of the locations to shop their restaurants or valet services but I still wouldn't do these shops (even if the fee was less insulting) as they want you to go back to the same hotel again and again and keep taking photos of the meeting board. At some point a manager would probably notice and kick you out.
There are shops that I happily do that many others wouldn't. But I can't see why ANYONE would do these.