Programmers and sysadmins have at times allowed themselves to insult users with the term, rtfm. But a going concern, like a fountain which might or might not contain drinkable water, does not need a sign detracting from its beauty, for all passers-by will be sure to notice a vagabond wearily making his way for a drink, and warn him if the water is not drinkable, and any vagabond would be sure to wait for a little to see what others are doing.
If a fountain is to be commissioned, the builders know they have a contract with the public. If we are to think about Utopia, we accept that the stones are laid one at a time, and don't round up all the vagabonds into a vagabond nest; we also know that a warning sign detracts from the beauty of something to the degree that we save ourselves the trouble of making beautiful things. At the public expense, then, we might have to get people to guard the fountain until such time as the information as to its correct use has become common knowledge.
In a Utopia nothing is immovable or unchangeable. It may so be that the designers decide that the fountain should have fish, or it may so be that it is no longer interesting to the public. In either case, the prefects will need to be hired again to warn people that a change is taking place.
Preferably by telling them to rtfm again.
The builders must remain untouchable, for what then would prevent the general populace from saving themselves the trouble of learning to read?