> I've actually been pressured to hire someone just to hold onto the req at a large company, with the up-front, stated intention to fire the person in a month or two and keep looking.

Wow, that is seriously fked up. While I got pressure to hire (one role I hired for was very specific so it took a long time to find a candidate), as long as I was actively sourcing/interviewing people, I never got too much flak. You've got to keep a hiring bar high... and not screw people over!