FYI: I’m a small (basement) coral farmer.
I agree “chop shops” are bad for the animals. Coral are usually regarded as only a product to them. However, I believe the perception of “white frag plug = chop shop” to be very unfair and misunderstood also. There are many reasons to remount a healthy aquacultured coral. Such as algae, cross encrustment, or a problem with the original plug. Some species don’t encrust on a plug at all also. But if you prefer a plug with algae on it, then certainly request one.
Imo, the best thing to do is ask the vendor. Stop being shy, and ask them how long they had the frag, and go from there. If you can’t see what you are buying before you pay, that’s your fault too. You probably wouldn’t buy a gallon of milk without looking at it first, for example. I despise the idea of “chop shops”, but I think if people stopped buying from them, then they’d change their methods. Demand dictates practice. However, some Reefers may like to gamble for a good deal, and will take the chance.