That's the thing, if someone's pickups are hidden like I describe above, waiting until the last possible minute to submit your own pickup won't make a difference in the result. But, in the OP's case, I'll admit getting skunked three times does reek of possible foul play.

I suppose a theoretical trip sniper might set up Crew Companion alerts for "Pickup Requests" via the Filter function. Doing this might alert the sniper to the OP's request in time to put in his own pickup. I honestly don't know why anyone would bother with this particular alert, I get too many already. Maybe they figure they will be able to trade/drop the trip later if there is demand for it? I dunno, but I do know a PDR might get a definitive answer.