This isnt a suggestion. Well a suggestion to fix it.

I tryed to send a friend -1fg. I get redirected to the goldlog page, which appears to be empty.
I didnt lose, or gain a fg, and neither did my friend. But i guess its a bug.

Maybe something to fix?

If it results in nothing happening why does it need to be fixed?

You can't send negative FG, you didn't lose / earn FG and either your friend so what need to be fixed?