Proper way of typesetting dot over indexed variable

Question

What is the proper way to put a dot over an indexed variable, like for Netwon's derivative notation? For typesetting reasons, I prefer \dot{x}_i, but my colleage argues that it's an operator on x_i and hence it must be \dot{x_i}, which looks hideous if the index is longer, like \dot{x_\text{max}}. It becomes ever worse since I want to typeset vectors in boldface using the bm package, but then the dot is boldface as well, and that is certainly incorrect. Who has some wisdom for me?

\documentclass{article}
\usepackage{bm}
\newcommand{\vect}[1]{{\bm {#1}}}
\begin{document}

Is it $\dot{x}_i$ or $\dot{x_i}$? What about $\dot{x_{max}}$? \par
And what about $\vect{\dot{x}_i}$ or $\vect{\dot{x}}_i$, 
or maybe better $\dot{\vect{x}}_\vect{i}$?

\end{document}

Which yields this:

Answer 1

Thanks. I can answer my own question from egreg's and David Carlisle's answers:

Use \dot{x}_{<subscript>} and \dot{\bm{x}}_{<subscript>}, since typesetting is not mathematics.