Escaping for plain links+discussion

I don't get it. In what context does this apply?

/* http://ourpla.net */

point is to be able to avoid autolinking

What about just using the rejected prefix what does !http://wagn.org/Home do?  That includes the ! character.  I think parans do it [](http://wagn.org/GerryGleason), actually ]{ and double quotes "mailto:[email protected]".  We could add backslash to the matcher, but supress it in conversion.  Or is what it does enough?