so curiosity got the better of me

it seems firefox doesn't work with the function, but ie does, which is cool in this case

<script language="javascript">
document.onkeydown = function (){
if (122 == event.keyCode) {
event.keyCode=0;
return false();
}
}
</script>

prevents maximization in ie, however, on my pc at least, it requires acceptance of activex... which is a bit much

maybe you can modify the code to get round the activex requirement though