The arguments and examples given for why the rule should be relaxed are rationalisations. So far what I've read is that the rule is either too inconvenient or not adheared to anyway, so let's amend the rule with 2 pages worth of exceptions, fine print notes and special conditions.
The wisdom of this rule in it's simplest form is that it assumes nothing about the individual's judgement or experience or anything about the model's ability to do harm.