If you assigned your hotkeys within Razor, there is a hotkey that disables all hotkeys within Razor that you can set. Check Hot Keys tab in Razor.
what about hotkeys that have no apparent location like control q (repeat last) and control w (previous statement) ? I've never seen the location of these hotkeys and they take up convenient positions for other hotkeys? A clear all of chat would be useful for these.
Here's a crazy thought but it's been working for as long as I can remember. Hit or hold the backspace key.
Not that my option was super affordable, but I think he probably gets that and just doesn't want to be bothered with backspacing 50 characters every time he wants to say something after some action. Although, I guess you're right that it is a crazy thought, to think he hadn't considered backspace. You crazy son.