Where I live, we don’t yet have those cards. I despise the idea of them and hate getting caught out by them (I’m looking at you Tesco and Lidl).
Normal price for something - 0.49 (in stores without these cards) But in their store it’s only that price with their ‘club card’ or ‘plus membership’.
Otherwise it’s 1.59
There are loads of other items with high markups.
BUT - the marked price is the normal store price to the inexperienced shopper of these data collecting stores, with the blind spot being the need to have a store card to get the ‘discount’. My full shop was an extra 103.46 altogether between the two stores (51.22 in one 52.24 in the other) rushing to get christmas dinner and dining and extras. Should be banned. /rant
The government doing a sick job of protecting consumers. /s


I guess it boils down to marketing etc. So. Maybe the government shouldn’t outright ban it, but it should definitely have stricter rules. The ‘discount’ price shouldn’t be allowed to be advertised as though it is the main price - with the original price being smaller and easier to go unnoticed. But also the reason why the cards exist should be more transparent. Data collecting. The people that do not have the cards are being charged more. But the people that do have them are being monitored more easily.
Now, I’m not one of those “muh free market” morons, but I also think that not every potentially-abusable business practice immediately deserves government regulation against it. By and large it seems that most customers really don’t care that much about this (myself included). The ability for customers to choose where they shop has regulatory power which I think a lot of people fail to recognise. If a behaviour is really repulsive, then customers will just not shop there, which provides a strong negative incentive against the behaviour in question, without any state intervention or enforcement resources required.
An example of this working in practice is the practice of restaurants attempting to introduce tipping in Australia (where it is not customary to tip). Whenever a restaurant frequented by locals tries to force them to tip or makes it awkward to not tip, there is an immediate and strong negative reaction to it from the customers which usually causes the restaurant to give up on the idea.