Plain TeX defines \Pr as
\def\Pr{\mathop{\rm Pr}}
LaTeX and ConTeXt define it similarly (with some syntax sugar around the choice of the font). To me, a more reasonable definition is
\def\Pr{\mathop{\rm Pr}\nolimits}
so that constructs like \Pr^{f}(X) look nice.
Are there any scenarios where the tradition TeX definition is more appropriate than the latter?
