Since you like analogies...
There is a supermarket that at the checkout has a bowl of candy that operates on the honour system.
If you push a button next to the bowl of candy an ad will play and you can take a piece of candy. The candy itself costs a fraction of a cent to the business and the business doesn't care to put anyone in place to monitor compliance with button pushing.
This system is known by everyone and operating in this way for decades so there is no deception towards the person at the supermarket.
Is it ethical to take a piece of candy without pushing the button?