The Title Bar is more commonly called the player bar, and when when MC is off (meaning play is stopped, not merely paused), it displays the application name just as you noted.
In my prior post, I was referring to whether there are any tracks listed at the bottom of the playing now view (not the player bar). I assume there were some tracks listed there in your test, since you say it did launch Spotlight (which is the same behavior that I see).
Did you test with no tracks listed at the bottom? If not, select all the tracks and hit delete. Then do the long click and hold in the player bar's track info area. For me, Spotlight will not launch no matter how long I click and hold. If it is launching Spotlight for you in this situation, then that's a problem.