Questions about the cast on mechanic

I'm leveling too many alts :) as is my habit. Just now getting to the cast on Sorcerer mechanics.

With something like Cold Snap or lightning warp, will the cast on auto target? Or does socketing those kind of things just waste space as they dont work even though the game will let you put it there?

Thanks for any help & information.

Lightning warp will auto-target and when i tried this it often teleported me backwards into groups i was trying move away from.

Also lightning warp + ball lighting socketed in a meta-gem can crash the game. :)

Good to know.

Thank you.