This claim isn't true. Being friendly is one such trait - it means one has more former comrades out there. Being well-known is another one. Being part of an organisation that gives rise to comradeship is a third.There's no trait that makes a person more capable of running into former comrades
In BW, the first is established via the derivation of Circles from Will. (The closest BW has to D&D's CHA stat.) The second is established via Reputation mechanics, and the third via Affiliation mechanics.
He kept a lookout for them, in a place where they might be around (ie in the neighbourhood of the old border forts along the river).what action did the character take to cause the meeting with a friend or comrade to happen?
The existence of these former comrades is already established at the very start of the campaign: Thurgon has a Reptuation (Last Knight of the Iron Tower) and multiple relevant Affiliations (including with the Order of the Iron Tower) which establish the existence of these NPCs. More generally, it is established that Thurgon has been alive for nearly 30 years, in that time serving as a page and a squire and a knight of his order, and hence has met many people. (Other Affiliations include with the nobility and with his family; he has since also acquired an infamous reputation in Hell, as an intransigent demon foe.)Normal flow being: current fiction -> character action -> mechanic resolves -> updated fiction
The flow here being: current fiction -> invoke mechanic -> updated fiction (including adding the NPC's, the characters action/interaction with them and the outcome of that interaction including any complications)
So the flow is: current fiction, which includes the fact that Thurgon has former comrades and also that he is in the neighbourhood of the old border forts -> character action (ie keep an eye out for former comrades) -> mechanic resolves -> update fiction (ie Thurgon and Aramina meet Friedrich, a former member of Thurgon's order).
The first example of a mechanic I can think of that resembles this is the Streetwise mechanic in Classic Traveller (1977). There is the Yakuza's contact mechanic in original Oriental Adventures, though it works on a rationing basis (so many contacts per level) rather than on a check basis.
The attempt over 30 years later to paint this sort of mechanic as deviant in some fashion, and as not involving action resolution that flows from the established fiction, is not plausible.