doesn't every brokering agent give his client details to the air operating company on every flight, so surely the jet companies know who everyone's client is, during the flight? And especially if going to USA they need to details for security.
Well, yes they do, but there is an understanding between operators and brokers that the operators will not chase after a brokers clients directly, partly down to a gentlemans agreement, but mostly (I suspect) down to resources and time. However, when the operator in OWNED by a brokerage you can bet details will be passed back for a marketing department to research and target at their leisure.