Rot13 to avoid unintentional side effects of URL activation? What could possibly go wrong apart from a) the mangled URL still having side-effects and b) only th

Rot13 to avoid unintentional side effects of URL activation? What could possibly go wrong apart from a) the mangled URL still having side-effects and b) only the non-mangled URL serving malware, thus totally defeating the purpose of this "safety check"?