I know it certainly could never happen to me, but I wouldn't say it's impossible. People are wired extremely differently, and sometimes the same person's way of loving can change drastically based on who they're in love with. There are just too many variables for love at first sight to be completely ruled out.
The closest I've experienced is getting a first glance at someone and knowing I want them in my life, but that's only as a resource or possible friend, never in a lustful or romantic way. So far it's never worked out, either. Much better of with connection at first conversation.