Why can Caitlyn still place invisible traps behind towers?

It's not an issue with Caitlyn but with traps. Nidalee can do it, too, for instance. Obviously her traps aren't necessarily as dangerous... but to make it seem like its a problem of Cait is misrepresenting the issue. All they need to do is add a very visible outline that makes it show up when blocked by another unit. Something akin to oracles or red trinket showing invisible units in bushes or what have you.

but when teemo does it... kappa.