Indeed!(Kinda)
on *:TEXT:!request*:#: {
if (%Switch == false) { halt }
;Insert the rest of your code here.
}
A simple "if" leading to a /halt will suffice. Now for the "Kinda" part. I don't know how to tell the "on Text" event to literally stop listening, I just know how to make it shut up.
The only thing you have to come up with is a method to make %Switch true/false.