They're keeping something from us...
From Patch Chat 6.15:
In solo queue, we think that champions who can poke towers early on (Caitlyn?) might have the option of taking towers somewhat earlier, but that it probably won’t have much of an impact.
https://31.media.tumblr.com/e4f2dc0189be4e0cdb9d5e040c19e062/tumblr_inline_nch2n1wQAj1rfs101.gif