No duplicate tabs?

A script command or add-in could easily do that now, and work however you wanted (e.g. just in the current window, or half of the window, or across all windows and listers).

It can also be done automatically as soon as you change folders or similar, as im TBone's CloseTabSiblings script that already exists: [Event: CloseTabSiblings (autoclose equal tabs in tab-row))

Note that your hotkey example could use NEWTAB=findexisting to avoid the situation entirely, so there's no mess to clean up.