It's also a matter of dealing with the problem now while it's right in front of your eyes and you remember. Generalizing here but assume 6 months later this ra

It's also a matter of dealing with the problem now while it's right in front of your eyes and you remember. Generalizing here but assume 6 months later this rare duplicate happens for a very important customer so you can't just brush it off, you now really have to fix it. By then nobody remembers this code review so you don't even know if this duplicate is a one off rare event or if it is going to affect all customers. Fixing it in code review might have taken a few hours extra for one guy, now you sent the whole team scrambling weekend overtime just to find the issue and understand the implications.