I had tanks, one was a 4 footer, several smaller ones, about 12 years ago and after a few years left the hobby. TBO I did a lot of things wrong and like our friend in Scotland, feel guilty about it.
Now I have decided to come back and even though I learned a lot before, I felt it necessry to research on the Internet. And wow, how things have changed!
Yes, I saw all the so-called designer tanks but was not attracted to them simply because my research had shown the sizes and shape I and the fish I intended to stock it with, needed, and it certainly wasn't one of those. It wasn't a brain strain, just look it up, there's a mass of info out there and after a few looks you soon begin to wise up.
So there is not an excuse for failing to do one's homework at all if you have an Internet connection. It doesn't take long and passes some time in a pleasant and educational way
I am wondering if it is the shop assistants that do not guide people to a decent tank for their purposes, after all the buyer must have gone in and had a chat, one may think. But some folk are stubborn and if they have set their hearts on a particular item often cannot be budged off it.
There is a place for the designer tank, but probably not for tropical fish and maybe even no other kind of fish, but more to a planted 'picture' which would fit in well with the tank's looks and perhaps even the aim of the designer and the perceptions of those that look at it.
But after all that I agree it is wise to tread lightly with somebody who asks advice or comes on here pleased as Punch with their purchase. Perhaps in time they will see the mistake and look at increasing the tank size?
Angela