Riot "We want people to be able to respond to assasins"
Yeah I can respond, I can scream before I die now.
But in all seriousness I feel like top and mid lane cannot really escape ganks from certain champions right now. You can see them coming but you will die anyway even if you have a summoner up. If the jungler or laner has CC the burst damage that an assasin does is just way too much and you're dead whether you flash or not.