A comparison that isn't quite the same on one dimension doesn't invalidate the comparison... The dimensions I was comparing were those of temptation and of "missing out" on some free stuff. Still, not eating free pizza at the tech event take 0 time too. Maybe you'd argue that you have to eat sooner or later and food is already there so you can multitask it but by the same argument for many free X on Craigslist, you'll have to get an X sooner or later, it's already there so you can multitask picking it up while you go do some other errand. Or hey, ignoring Craigslist, look at that decent-looking free chair you're about to drive past going home from work...
Comparison is very accurate, not picking up free junk on craigslist takes 0 time, not eating the free food at the tech event (that you are already going to) takes 0 time.