Mathematica (and thus Wolfram Alpha) is unusual in it's use of brackets to enclose function arguments. Every other computer algebra system I've used has been content with parentheses. And NoScript is pretty much the leading edge for browser security, so if it thinks brackets are dangerous, they probably are and other browsers could follow at any time. Wolfram Alpha's direct use of Mathematica's notation in URLs seems a bit naive, and it wouldn't be the first time Wolfram embarrassingly misunderstood the way the web works.
