You are arguing for Universal Background Checks, but you are saying the mandatory system would not be mandatory...
Actually I'm not. While there is a loophole gray area if nobody answers the phone, is that a delay, can they proceed after three days, etc.-
The default action is to proceed if NICS does not answer back within their allotted time period.
I don't believe any of this would happen, I only use it as examples that the "presumption" is proceed, not deny.