That Safari has no preference to warn users when quitting or closing a window with multiple tabs open has always pissed me off. After all, Q is right next to W. TabStop to the rescue.
TabStop is a SIMBL plugin that displays a warning when you attempt to quit or close a window in Safari that contains multiple tabs. Very handy, if you’re used to keeping dozens of tabs around and you’re tired of accidentally Command-Q’ing instead of Command-W’ing. TabStop is a Univeral Binary.
Thanks to FreeMacWare for this most excellent tip.