I think I've hunt this down http://tools.ietf.org/html/rfc3986#section-3.3
If you follow the BNF for path, you have.
path -> path->absolute -> segment-nz -> 1*pchar -> \
unreserved / pct-encoded / sub-delims / ':' / '@'.
So it seems "everything" is allowed on path, I'll fix the diff.
