I've done this in-game before, its quite fun when many people do it
This is how it works: Do what the post says, run script in-game by typing /filename - must be in scripts folder - then a link (DONT CLICK ME) will appear in ooc channel, someone must click this link willingly, and a info window will pop up with another link (NO REALLY DONT CLICK ME), you must click that one, which will trigger the /say command. But only problem is you have to click 2 links and if you just mouseover the 2nd link you can see exactly what the script does.