Lelanya
Mentor
You can observe your bonuses with the Wonders connected and then observe them with the Wonders disconnected and compare the difference - that's what I did. I have also personally witnessed the score drop in a few instances that I could name; in fact I know of a player who crept up on rank 1, by connecting certain Wonders, fighting tournament briefly, then disconnecting. Some were surprised when he took over, lol, which was the point I suppose.@Lelanya : Aha, thanks Lel !! I did think it would be too good to be true... and being lazy (and averse to watching my Units die), I haven't tried it!
In short, you cannot prevent someone from adding 1 KP to a Wonder (without hurting yourself), and really, so what? Write them and thank them for helping, who knows, you may make a new friend.