Here "violated this precept" means that the work of architecture not be both inviting and functional for public use, and the "be unobtrusive" is a necessary condition to the precept, so violated the precept means that the work of architectures not be unobtrusive.
That's what Lawyer means, but I can't confirm , if u get any other examples, collect them to put here pls.
I think "violate the precept" means "violate the precept of "must be unobtrusive, therefore it's not functional". This is because unobtrusive actually means the opposite of "egoism".
To Valarie and Joe11, I think u're right, if "violated the precept" here means that the work of architectures not be unobtrusive, we would safely arrive at the conclusion as B mentioned.