I am less worried about receiving spam and more worried about not receiving good mails. Are you sure that Gmail's spam filter has zero false positives as well? If you are sure, how do you know? I can not check my spam folder manually because it contains thousands of mails.
At one point I was checking it religiously but I've come to trust it after never finding a legitimate mail in my spam folder after a long period of time. I still check it from time to time, and again, I don't find legitimate mail tagged as spam.
Most confirmation mails (and the like) end up in my Gmail junk folder. E-Mails from normal people never. And for me it has just become a automatic process to look in the junk folder for those.
