Units Often don't take the bait vs assasin comps with one non-assassin

Assassins rely on the back line moving towards their target but often they don't move even though they are out of range of the 'bait'. I've lost multiple games because once or twice or THREE times the opposing team sits still ignoring my non-invis champion and my assassins just jump to the frontline. Please the predictability of champion movement is reallllllly important for strategic integrity and fun.

the bait is literally in the opposite corner and they dont move (unless they have an assassin and thats the only one that moves) its pretty dumb. Maybe their assassin blocks all pathways to the unit? but that seems really unlikely