On subject of contact to other people rather that taking their picture, I have a very close approach to Jonathan and Ollie. Though my friendship has never grown to that extend, I never hesitate to open the discussion when I see a common ground and most of time I have enjoyed the end result. For most cases, the co photographer will receive a paper with few web sites such as WPF's url address from me and I have come to know interesting things in return.
The only situation that makes me to be hesitating is when someone get interested to know about my gears etc when I am just ready to take that expiry time approaching shoot that may never happen again, so on those rare occasion, I may use one of the old tricks of book such as "no comprende" and if the guy continue in fluent Spanish, then leaves me with no more choice to repeat myself with emphasis on NOOOOooooo.
On a side note there has been few occasions when things happened that may not be forgotten easily. One to share here was to see a guy behind one of those cannon Canon nice white L 600mmIS taking competition surfers picture in Waikiki Hawaii in a spot that is far to the east of Waikiki beach, close to Diamond head, where quite far from shore (Unlike most other parts of this beach) big waves are formed and usually big boys and big girls are only found here with no newbes. This is on end of a nice park with good tree shades etc where for a good reach you might be in need of 600mm plus a 2x extender to say the least. Well not knowing the place well, with my surfer son somewhere far to the other end in the water I though of taking some pictures in this location where I was lucky to find a free parking spot. I could not stop myself not to initiate talk to the young photographer behind the shinny gear that had a very professional look. The guy did not even turn head or let me thing I exist.
Well I thought he might be deaf-mute or just out of a not so happy discussion with his wife. So didn't mind at all. But in no time the surrounding draw my attention with several sexy gentlemen, many wearing thong!!!!! others hand in hand and few even in more intimate conditions. Well no doubt this poor photographer has had many probably not so decent proposal according to his taste in past, making him prefer not to talk at all....