My 2 year old DS has taken to doing this - in Tescos, even in the library fgs. The library's a no brainer - obviously I remove him from said place ASAP. The supermarket's different though - we have to eat. I've started ordering online, but I still need to go from time to time.
The right thing to do, I believe, is ignore him. But oh the looks, and the shame. I used to be that woman who looked, nudged her husband and tutted. I used to be the one who thought parents of screaming toddlers were bad parents. So I lamely try to show displeasure: "that's enough", "I won't tell you again etc.". But I know it's futile - it's just for show.
Tell me what I should do! Ignore or react? What do you do?