origin: (1809) debated origins
I was recently at a nice party and a young woman was wearing a jersey with the logo of our local baseball team. The woman next to me politely commented on it, and the young woman beamed how much she enjoyed rooting for them. This was followed by an older man asking pointedly, "Who was in the bullpen today?"
It seemed as if he was testing her, but the truth was...I was only half certain what a bullpen was myself and I certainly didn't know who was in it that day. In fact, it's not always a focal point or expressly shown on screen, and audio-wise it can get lost in the non-stop banter of the announcers. Well, bullpen turns out to be a slightly interesting word beyond mere "gatekeeping" for baseball fans during baseball season. *ahem*
While it can be the area for the relief pitcher to warm up (or refer to several "relief pitchers" as a group), it can also be used to describe a communal workspace area -- often thought of as a way to also pit them against one another or at least inspire them to crave more privacy -- which dovetails nicely into the third definition: a grouping area for prisoners or migrants. tl;dr: a warm up and/or containment area.
So, in sports it is basically positive, but in work environments it may go either way, although that reflects the usage as a negative -- when people are held captive or in limbo. However, what's really interesting about the word bullpen is that no one knows exactly why or when it came into use for baseball. So, ask your next gatekeeper that trick question should the chance arise!
BONUS QUESTION: Are you a fan of baseball? Did/do you play or enjoy watching any sports? *contest reminder