I was driving around on GTA Online and ended up finding someone who was trying to do one of the MC sell missions with the slow delivery vans and instead of blowing up his shipment I pushed him with a fast car to give him a speed boost which helps dramatically. I made sure to honk my horn whole constantly, as did he, so we knew both know what I was doing and he didn't have a mic and could only acknowledge my reminding him I'm not a threat with horn beeping. I also would give him a helicopter ride after each truck so I could save him time in between fetching the delivery vans. Took about 15 mins and I just left to drive around on the highway he was doing the very last package.
He tried to offer me money and I declined.