My way, yes chopping a bridge would be considered an attack. Because to break the rope you have to roll to hit, deal damage and so on. Mechanically, its the same thing as hitting an opponent, so it makes more sense (to me) to treat it the same way. (Untying a rope someone is climbing up isn't an attack, if anything its a function of the Use Rope skill, and I can't get around to having skills spoil Invisibility.)
As for the Wall of Iron, even though you aren't rolling an attack, it's still an attack. Remember, my solution was to vastly simplify the rule as Invisibility fails if you make an attack. It's hard to argue that pushing hundreds of pounds of iron on someone isn't an attack. Its the difference between swinging your sword and making an attack roll. You can swing your sword all day around all sorts of people, but if you actually want to hit and do damage, you have to make an attack. Its in that mechanical distinction that I think Invisibility should fail.
Like I said, my way clears up 99% of the problems. There's always going to be hinks in the line. Like, for instance, dropping a rock on someone's head. What's the difference between dropping a 40lb rock off a wall onto the ground, and trying to drop it on the guy standing at the bottom of the wall? The simple answer is, in the second instance, you have to roll to hit (or like wall of iron, set off an area effect attack, but you probably aren't using a rock that big). It doesn't solve the problem of two identical actions have different results, but seeing that there is a clear mechanical difference, its a lot easier to adjudicate.
Besides (to me), the difference between making an attack and dropping a rock is pretty clear. No one is likely to get confused on that point. As opposed to what happens in the current rules when Jhualee's 4th question comes to pass. (Or, in situations where the RAW isn't confusing, I don't think my way is any more confusing. But in situations where the RAW is confusing, I think my way makes a lot more sense. Though I feel obligated to point out the first rule of house ruling: No one has a problem with a rule they made up.)
