That's not manipulation, that's just plain old-fashioned blackmail. Now in my current campaign, I had the PCs turn down a mission I offered them because it was against the King and therefore treasonous. (I don't think that in itself bothered them, they just didn't like contemplating the possible repercussions.) And now the King, or at least one of his advisors, has come to them asking them to perform exactly the same mission. With the same horrible repercussions if they don't go for it.

I have let them know that they have the option to run away and hide. Or at least try to. Nearest border of the kingdom is several hundred miles away.