Well the problem is not the deck of cards they carry.
Even lounges put signs outside that tell you which cards or programs they have so you don't have to ask or they can just point you to it.
The problem is that they pull it out to let their whole gang inside the lounge with just one single individual cards.
I get it if it is a single person or even a single family (wife/kid) but not the whole family tree and bringing in uncle, aunties, grandparents, parents, cousins, nephews, etc into the lounge for "free" with just someone else's card trying bypass and skip the rules. I've seen this personally in nearly every lounge around and specially in Delhi there's always huge groups outside.
More over they argue, fight and beg the staff to let them do it and then the line starts building up and everyone also gets into a mood including the staff. That's when it becomes a problem. There's nothing to argue people, it's not tax filing, it isn't complicated. The rules and access is clear and simple. Stop trying to abuse it.
Moreso usually people trying to pull such stunts will try other "tricks" like taking food and drinks for "free" for the flight, drinking all the alcohol they can, among other things.
Just yesterday I saw a guy waste in the entry of the lounge wasting everyone's time trying to argue why he should be able to take away food after he was told NO. Then he spends to take forever asking questions to see if the food is good and whether if it is worth it using a free entry into this lounge. Mind you, it was one of the worst lounges countrywide.
Also not sure whether this has had any influence over the dramatic drop in quality of everything, but I've specially noticed the food to be fairly bad this year.
Even AMEX Centurion lounge in India is a disgrace to it's name. They don't have too many lounges worldwide and they are pretty good, but the one in Delhi compared to ANY of the others it's a laughing joke... Incredibly small and lacking facilities.