Silent No's and the like

So, I just got done reading a bunch of responses to a friends' LJ, regarding a blanket invitation she made. Several of the comments she received were something to the extent of 'if someone doesn't respond, at all, that means NO.' So here's my question, due to the overwhelming *lack* of response we've gotten to our Halloween Party invitation, should we just cancel the dang thing & save ourselves the hassle?