Well, to be fair, I was selling 3,000 parcels at one point. I admit I thought about a macro, but ultimately didn't. With the snowball cannon and normal snowball I amassed that amount in about three weeks? A fair amount of using my companion, though still did throw at other players.
Even if you're actually playing the game, it's not hard to gather parcels. My cannon and snowball were on my quickbar, and I would throw them at anything whenever I remembered to.
That being said, I did have about a 2-4 hour period each night from Dec 13 - Dec 25 where I would be just standing on the fleet for Hannith's giveaway events. (12 days of christmas event that she hosts on BC every year), where I could just chat and throw snowballs, so that helped too.