There's no need to hack Views for that. (Really, don't, you'll live longer.)
I believe you want to set the default value of the filter to empty, and then "use default" on the exposed filter. Or something along those lines. It may vary with the field type, but I know it is possible to setup an "empty by default" View because I've done it before myself.
I don't actually see any way to do that.
The hack works, however, and was pretty painless. Maybe 8 lines of code altogether.
Thanks.