Obviously I would never give in to stuff like that but it makes me wonder if this is common and what to do about it.
Regardless, I think this behaviour should be actively discouraged by naming the parties involved as encouragement for them to either join the community in an honest fashion or alternatively to try their luck elsewhere.
The company has obviously seen you post a lot to HN. Do they think you're a sucker?
-edit: and if you do, what do you get out of it? You could ask for a favour in return, or tell them to post it themselves and you might just upvote it.