I'm with
@JamesL on this one.
Will always give an unsure decision to the defending team, whether goal kick v corner or a throw.
To the OP - once I'd established this principle in my head, it really helped my game. Much less indecision from me - when I genuinely don't know what happened (and, often, no one else is completely sure) I don't sweat it: defending team ball. One less thing to think about, decision made, lets get on with game, players respect that.
Addendum: I don't think it really matters if you always go with the attacking or defending team on throws, just as long as you are consistent. When you genuinely don't know, you've got to do something!