Re: No defence?
Aikido defence - Maai...distance.
Non Aikido defence - look up The Fence & Geoff Thompson.
anyone thats done even the smallest amount of verbal training will recognise the symptoms of an impending attack. You don't need waving hands or great big signals...a single word, a nod of the head...a fixed stare or gritting of the teeth. Any of these are clues that someone is puffing themselves up for a bit of reputation building at the victims expense.
Of course there are no guarantees....the real circumstances here are hidden but you don't need to be a genius to work out that standing in front of someone and arguing can be a recipe for disaster.