In this light the sucker punch can be anticipated by an experienced "street" person.
But I thought everyone agreed that a sucker punch is completely unanticipated...granted, an experienced person will presumably be more aware and avoid being sucker-punched more easily than an untrained person, but even so, isn't a "sucker punch" by definition, one which is not expected? Whether you're a drunken idiot or a hardened street thug or even an expert martialist, surprises do happen. I know that many will disagree and maybe it is possible to heighten your awareness, discretion, and avoidance skills to the point where you can never, ever be taken by surprise. But I have never met anyone who claims to be immune to surprise attacks, and even that assertion, in my opinion, would be quite dangerous and in fact increase the chance of being taken by surprise. After all, surprises are what happen when you do not expect them to, therefore, if you assert that you cannot be taken by surprise, it's actually easier to surprise you, since your mind does not accept the possibility.
OK, I know that's a downright silly, circular, argument, but I see this so often in discussion of martial arts, when people have questions about particular situations, the response is so often "just avoid those situations." Good advice, of course, but do prevention and preparation have to be mutually exclusive? Or should everyone who posts a question about a particular situation preface it with "...given that you were not aware enough to avoid Situation X, you cannot run away nor talk yourself out of it, how can you defend yourself in Situation X?" Can't we assume that martial artists know that awareness, avoidance, and discretion are critical to personal safety? And I don't agree with the poster who says it's not terribly difficult to keep people who might conceivably punch you out of arm's reach and that surprise attacks don't happen as often as is perceived. But I don't have any statistics to back this up, so let's say they don't happen too often. Even so, it only has to happen once to end a life! And sometimes people do sense the danger, and try to get away, call for help, even fight for their life, but they are killed anyway. Not just amateurs, even professionals are surprised, not just in military ambushes, but when ordinary people suddenly and unexpectedly turn violent, and I don't think it's always accurate to say that awareness would have saved them. That's one of the hard things about life, that good people who are highly trained with much experience are still taken from us unexpectedly. And when such people are killed, others say, "How could this happen to so-and-so, he was so careful, so aware, and with all his expertise, why didn't his skills save him?" I saw this response to the murder of one of the most esteemed of our instructors, and I don't understand it. I'm not a religious person, but I also know I'm not immortal, and I don't believe that it is possible for us to develop the capability to foresee and prevent death, all we can do is increase the odds and hope the universe will look kindly upon us in our most dire situations.
Even leaving aside violence from other people, danger, by its very nature, is so often unexpected:
Some folks die by a lightning bolt or car wreck...despite how good they are at self protective skills and awareness.
I guess the point of my rather long post is, why not prepare anyway, even if you're confident you can avoid such situations, there's no harm and maybe a lot of good in learning the most effective means of surviving extreme situations. I think the original poster's question is a good one, and resulted in many informative responses...including the suggestions about awareness, avoidance, and discretion.
An attack from behind, I feel, is better classified as an ambush. Therefore, the avoidance principle takes on a new meaning. Usually an ambush properply planned by an enemy is unavoidable as he picks the time and place and depends on deception for success.
Ambush, sucker punch, surprise attack...I think the original poster was asking how to handle such situations, not what to call them.
Best wishes,
Rachel