The trouble is, somebody sees a fishing boat on a similar course and leaps to an immediate conclusion. Personally, I think that any 'pirate ship' would have no difficulty whatsoever catching the average yacht either under sail or power, so I have to say I discount most of these so called 'encounters'.
As far as sailing in convoy is concerned, exactly what use is that? Safety in numbers? When confronted by an AK47? I'm still undecided on the 'route back', my planning stops in NZ at the moment but the Cape option is a tough trip. Mind you, I've spoken to one couple who did it and they reckoned the trip from Cape Town north was the best sailing they had the entire trip.