tmux 3.2 changed the default 'mouse' option to on — how to keep pre-3.2 behavior across mixed terminals

After upgrading from tmux 3.1 to 3.2, the global mouse option now defaults to on. This means mouse-driven pane resizing, pane selection, and window switching are active even in configurations that never set the option explicitly.

The practical complication is that the effect depends on the terminal emulator's support for DECSET mouse reporting sequences (1000 for clicks, 1002 for drag, 1003 for all motion). On terminals with incomplete support — older xterm builds or Windows Console, for example — the same tmux configuration may behave inconsistently: mouse input may be ignored, or interpreted as stray keystrokes.

The goal is to restore the pre-3.2 behavior (mouse off) in a way that works reliably across a mixed fleet of terminal emulators, without breaking environments where mouse support is actually desired. Verification so far is limited to observing that tmux show-options -g mouse reports on in a fresh session on 3.2+.

Should the override be set globally in ~/.tmux.conf or scoped per session? Is there a documented way to conditionally enable mouse only when the terminal advertises proper mouse reporting? Does setting mouse off have any side effects on copy-mode selection behavior that should be accounted for?