I know this is an oldish post, but....
Is the moderation or personal views of the moderators not a little heavy handed here - 4 mods/admins with strong views on one post? Not sure other opinions are really getting a chance.
I am sure all the admins/mods are all very experienced, but this post comes across quite one-sided to me. Especially the mod-after-mod posts, one after another, confirming their agreement/allegiance with one another's point of view; which excludes other opinion by the nature of posting.
Whether or not carpet is the right solution, the advice appears based on opinion only. Unless we can cite examples of scientific test and proof (or any scientifically backed up statement) of leeching of chemicals in to the soil, etc, then this looks like opinion. CAPITAL letters or BOLD do not make the opinion more factually correct.
My view is that I would use carpet, plastic sheet (used it before and it was OK, kept the space covered, hence manageable, until the next season when I could cultivate it; but had no long term weed killing effect as they all came back as soon as it was lifted), or glyphosate (used very effectively for 7 years +) to try and keep on top of a patch of earth that I could not otherwise manage; depending on which ever solution I could financially afford. I would take on board experience from people like John and lift/change the carpet before it became a problem, but not be influenced by the online equivalent of SHOUTING.