Builders, contractors, and yes architects have had training that gives them more indepth knowledge about homes and construction than your average fireman or doctor or teacher or whatever. With this in depth knowledge comes a greater burden on you to DISCLOSE DISCLOSE DISCLOSE when you know there is a property flaw. So if you do not disclose a problem, and later the buyer finds out you knew about it (or SHOULD HAVE known about it) someone with greater knowledge/experience will be held to a higher standard.
For example, if you do not disclose that there is dryrot around the door frame and the buyer finds it after the sale, he could sue you for not disclosing. If you're a doctor, you might say "I don't even know what dry rot is, so how could I know my house has it?" The judge might believe the doctor. But a contractor or a professional -- not so easy to say you didn't know it was there.
Bottom line: no matter what your profession, DISCLOSE anything you know that is a problem/flaw with your property so it doesn't come back to bite you later.