Board Thread:Arrow discussions/@comment-1783334-20170516181147/@comment-24152851-20170725152020

They still repeatedly say they like to keep Arrow grounded. Even when sci-fi/mystical stuff gets introduced, like Ray Palmer and Damien Darhk, they end up moving over to other shows.

The Canaries are a special case due to how heavily that is in Green Arrow mythology. And even then, it's a relatively minor bit of fiction, since the Canary Cry had already been done using a device rather than meta powers.