Invisible hearing aids and other frauds

I was very upset to discover today that a shop in Cottingham (where I live - the village not the shop) has taken away their “Invisible hearing aids - 475 pounds a pair” sign. I really wanted to get a photograph of that sign.

The way I see it, advertising things like this is fraught with fraud potential.

“I say, there’s only one hearing aid in this box”
"That’s because the other one is switched on”
.. and so on.

They’ve now have a sign that that says “Free Eye Tests”. I can see fraud potential here too:

“We’ve done your test, that will be fifty pounds please”
”Hang on, the sign says that you do eye tests for free”
”Ah yes we do, but the charge is for testing the other eye. That costs fifty pounds….”

Sometimes I consider myself a great loss to the world of commerce.