Worth remembering that when an Engineer signs a report, such as a home inspection, they are personally liable for any errors in it (I believe it may be similiar in other lines of work but I only have experience in the Engineering field).
If they completed a report, failed to mention an issue with drains and those drains later collapsed, the Engineer who completed the report and failed to mention the issue could be (or at least opens up the possibility of being) sued.
For that reason alone most Engineers will take great care to include absolutly ever issue they identify in the report.
There is also an issue with verbal "advice". If a builder suggests something to a client and the client goes down that route the onus is on the client to ensure it's correct. If an Engineer suggests something in casual conversation (relating to his area of expertise obviously), due to the nature of the qualification, this is considered as expert advice and the Engineer can be held responsible for any errors.
To quote one of our lecturers before we went out into industry, "If they don't make you say something, then don't say a damn thing!".