I guess you only buy bug-free software, then.
But seriously, isn't it better to see what's wrong and ask how the worse-looking risks are mitigated?
I guess the answer is about the general business culture, i.e. whether you're more likely to lose your job when the shit hits the fan if you say "I made an information-based decision and unfortunately the risk materialised" than if you say "I know nuffin'... they said there were no bugs".
Personally I'd get rid of a buyer who gave me the second answer, but I that's just me.