Perhaps we are being a little hard on this person. My question is are you all saying 30 gallons is two small for one discus, or does the one discus per gallon still apply or does the latter indicate exceptions to the rule?
Truly when I first tried discus they were wild. There was little info out there at keeping as a hobby, and a lot of people trying their hands at breeding them. I was one and getting two wilds back then was considered OK. You had to turn to people like Wattley and others for advice. You did your best with little info. You tried different methods and you experimented.
Today most of the discus are tank raised with BBs. That to me is much like being in a glass zoo, but those fry are used to it, and would probably be stressed out in any other situation. The reasons for raising discus in BB, with 50% water change daily should be understood for it gives the easiest the quickest and satisfying results. It is not the only way to do things however. If you do choose to go out of the box, then you should have the knowledge, the patience, the work ethics, and the wisdom to call for help when needed. That being said, these people, in forum land, are usually experienced and have had their share of experimentation, successes, and failures. So you can gain from their wins and their loses. Many hands on-ers need to learn from personal experience. We are all fortunate to have such a forum, along with the access to experienced keepers, sometimes opinionated, sometimes generous, but most of the time are willing to aid in our personal knowledge and successes with Discus.
LFS think in a temporary time frame.
They hope not to keep the fish for a long time.
My question to you is do you think your fish is a living creature or an ornament? If you care about the fish's well being then you are going to be on this forum, asking the whys and the hows. Perhaps then taking that knowledge and applying it to your needs and expectations. You may well push the envelope, do your own thing, then if something goes wrong you have the knowledge and wisdom from the forum to fall back on.
You might after keeping one for a while want to keep more.
I for one have no problems with keeping one discus as apposed to ten discus. I figure if you can kill one discus just as easily as you can kill ten. I prefer it be one then ten.