That would unbalance the game and make Settlements pointless. ES will probably never implement it. TCs on settlements only is a major balance feature, placing TCs anywhere would turn the Heroic age into the 'make lots of TCs all over the place' age.
"Sometimes I really think people ought to have to pass a proper exam before they're allowed to be parents. Not just the practical, I mean." - Susan Sto Helit
"It's not fair to have a battle of wits with an unarmed opponent."